From 62c142ac70dbf8b4993352e931ab6c76e7213cdb Mon Sep 17 00:00:00 2001
From: Simon Scholz <simon.scholz@iws.uni-stuttgart.de>
Date: Wed, 20 Dec 2017 15:10:15 +0100
Subject: [PATCH] [doxygen] fix doxygen in fluidstates

---
 dumux/material/fluidstates/2p2c.hh            | 86 +++++++++++------
 dumux/material/fluidstates/CMakeLists.txt     |  3 +-
 dumux/material/fluidstates/compositional.hh   |  2 +-
 dumux/material/fluidstates/immiscible.hh      | 89 ++++++++++++++----
 .../fluidstates/isothermalimmiscible.hh       | 83 ++++++++++++++---
 dumux/material/fluidstates/nonequilibrium.hh  | 93 +++++++++++++++----
 .../fluidstates/nonequilibriumenergy.hh       | 20 +++-
 .../fluidstates/nonequilibriummass.hh         |  6 +-
 dumux/material/fluidstates/pressureoverlay.hh | 92 ++++++++++++++----
 dumux/material/fluidstates/pseudo1p2c.hh      | 56 ++++++++---
 .../material/fluidstates/saturationoverlay.hh |  9 +-
 .../fluidstates/temperatureoverlay.hh         |  2 +-
 12 files changed, 428 insertions(+), 113 deletions(-)

diff --git a/dumux/material/fluidstates/2p2c.hh b/dumux/material/fluidstates/2p2c.hh
index c28847cd58..f69efa5231 100644
--- a/dumux/material/fluidstates/2p2c.hh
+++ b/dumux/material/fluidstates/2p2c.hh
@@ -18,7 +18,7 @@
  *****************************************************************************/
 /*!
  * \file
- *
+ * \ingroup FluidStates
  * \brief Calculates the 2p2c phase state for compositional models.
  */
 #ifndef DUMUX_2P2C_FLUID_STATE_HH
@@ -33,8 +33,7 @@ namespace Dumux
  * \ingroup FluidStates
  * \brief Calculates the phase state from the primary variables in the
  *        sequential 2p2c model.
- *
- *        This boils down to so-called "flash calculation", in this case isothermal and isobaric.
+ * This boils down to so-called "flash calculation", in this case isothermal and isobaric.
  */
 template <class Scalar, class FluidSystem>
 class TwoPTwoCFluidState
@@ -51,10 +50,18 @@ public:
 
 public:
     /*!
-     * \name acess functions
+     * \name access functions
+     * \todo doc me!
      */
     //@{
-    /*! @copydoc CompositionalFluidState::saturation()
+
+    /*!
+     * \brief Returns the saturation \f$S_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The saturation is defined as the pore space occupied by the fluid divided by the total pore space:
+     *  \f[S_\alpha := \frac{\phi \mathcal{V}_\alpha}{\phi \mathcal{V}}\f]
+     *
+     * \param phaseIdx the index of the phase
      */
     Scalar saturation(int phaseIdx) const
     {
@@ -65,38 +72,63 @@ public:
         return 1.0 - sw_;
     }
 
-    /*! @copydoc CompositionalFluidState::massFraction()
+    /*!
+     * \brief Returns the molar fraction \f$x^\kappa_\alpha\f$ of the component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The molar fraction \f$x^\kappa_\alpha\f$ is defined as the ratio of the number of molecules
+     * of component \f$\kappa\f$ and the total number of molecules of the phase \f$\alpha\f$.
+     *
+     * \param phaseIdx the index of the phase
+     * \param compIdx the index of the component
      */
-    Scalar massFraction(int phaseIdx, int compIdx) const
+    Scalar moleFraction(int phaseIdx, int compIdx) const
     {
-        return massFraction_[phaseIdx][compIdx];
+        return moleFraction_[phaseIdx][compIdx];
     }
 
-    /*! @copydoc CompositionalFluidState::moleFraction()
+    /*!
+     * \brief Returns the mass fraction \f$X^\kappa_\alpha\f$ of component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The mass fraction \f$X^\kappa_\alpha\f$ is defined as the weight of all molecules of a
+     * component divided by the total mass of the fluid phase. It is related with the component's mole fraction by means of the relation
+     *
+     * \f[X^\kappa_\alpha = x^\kappa_\alpha \frac{M^\kappa}{\overline M_\alpha}\;,\f]
+     *
+     * where \f$M^\kappa\f$ is the molar mass of component \f$\kappa\f$ and
+     * \f$\overline M_\alpha\f$ is the mean molar mass of a molecule of phase
+     * \f$\alpha\f$.
+     *
+     * \param phaseIdx the index of the phase
+     * \param compIdx the index of the component
      */
-    Scalar moleFraction(int phaseIdx, int compIdx) const
+    Scalar massFraction(int phaseIdx, int compIdx) const
     {
-        return moleFraction_[phaseIdx][compIdx];
+        return massFraction_[phaseIdx][compIdx];
     }
 
-    /*! @copydoc CompositionalFluidState::density()
+    /*!
+     * \brief The mass density \f$\rho_\alpha\f$ of the fluid phase
+     *  \f$\alpha\f$ in \f$\mathrm{[kg/m^3]}\f$
      */
     Scalar density(int phaseIdx) const
     { return density_[phaseIdx]; }
 
-    /*! @copydoc CompositionalFluidState::viscosity()
+    /*!
+     * \brief The dynamic viscosity \f$\mu_\alpha\f$ of fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa s]}\f$
      */
     Scalar viscosity(int phaseIdx) const
     { return viscosity_[phaseIdx]; }
 
-    /*! @copydoc CompositionalFluidState::partialPressure()
+    /*!
+     * \brief The partial pressure of a component in the n-phase \f$\mathrm{[Pa]}\f$
      */
     Scalar partialPressure(int compIdx) const
     {
         return partialPressure(nPhaseIdx, compIdx);
     }
 
-    /*! @copydoc CompositionalFluidState::partialPressure()
+    /*!
+     * \brief The partial pressure of a component in a phase \f$\mathrm{[Pa]}\f$
      */
     Scalar partialPressure(int phaseIdx, int compIdx) const
     {
@@ -104,7 +136,8 @@ public:
         return pressure(phaseIdx)*moleFraction(phaseIdx, compIdx);
     }
 
-    /*! @copydoc CompositionalFluidState::pressure()
+    /*!
+     * \brief The pressure \f$p_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa]}\f$
      */
     Scalar pressure(int phaseIdx) const
     { return phasePressure_[phaseIdx]; }
@@ -115,12 +148,19 @@ public:
     Scalar capillaryPressure() const
     { return phasePressure_[nPhaseIdx] - phasePressure_[wPhaseIdx]; }
 
-    /*! @copydoc CompositionalFluidState::temperature()
+    /*!
+     * \brief The temperature within the domain \f$\mathrm{[K]}\f$
      */
     Scalar temperature(int phaseIdx = 0) const
     { return temperature_; }
 
-    /*! @copydoc CompositionalFluidState::averageMolarMass()
+    /*!
+     * \brief The average molar mass \f$\overline M_\alpha\f$ of phase \f$\alpha\f$ in \f$\mathrm{[kg/mol]}\f$
+     *
+     * The average molar mass is the mean mass of a mole of the
+     * fluid at current composition. It is defined as the sum of the
+     * component's molar masses weighted by the current mole fraction:
+     * \f[\mathrm{ \overline M_\alpha = \sum_\kappa M^\kappa x_\alpha^\kappa}\f]
      */
     Scalar averageMolarMass(int phaseIdx) const
     {
@@ -134,7 +174,6 @@ public:
 
     /*!
      * \brief Returns the phase mass fraction. phase mass per total mass \f$\mathrm{[kg/kg]}\f$.
-     *
      * \param phaseIdx the index of the phase
      */
     Scalar phaseMassFraction(int phaseIdx)
@@ -148,10 +187,10 @@ public:
         }
         return nu_[phaseIdx];
     }
+
     /*!
      * \brief Returns the phase mass fraction \f$ \nu \f$:
      *  phase mass per total mass \f$\mathrm{[kg/kg]}\f$.
-     *
      * \param phaseIdx the index of the phase
      */
     Scalar& nu(int phaseIdx) const
@@ -165,7 +204,6 @@ public:
     //@{
     /*!
      * \brief Sets the viscosity of a phase \f$\mathrm{[Pa*s]}\f$.
-     *
      * \param phaseIdx the index of the phase
      * @param value Value to be stored
      */
@@ -175,7 +213,6 @@ public:
 
     /*!
      * \brief Sets the mass fraction of a component in a phase.
-     *
      * \param phaseIdx the index of the phase
      * \param compIdx the index of the component
      * @param value Value to be stored
@@ -187,7 +224,6 @@ public:
 
     /*!
      * \brief Sets the molar fraction of a component in a fluid phase.
-     *
      * \param phaseIdx the index of the phase
      * \param compIdx the index of the component
      * @param value Value to be stored
@@ -198,7 +234,6 @@ public:
     }
     /*!
      * \brief Sets the density of a phase \f$\mathrm{[kg/m^3]}\f$.
-     *
      * \param phaseIdx the index of the phase
      * @param value Value to be stored
      */
@@ -220,7 +255,6 @@ public:
 
     /*!
      * \brief Sets the phase mass fraction. phase mass per total mass \f$\mathrm{[kg/kg]}\f$.
-     *
      * \param phaseIdx the index of the phase
      * @param value Value to be stored
      */
@@ -230,7 +264,6 @@ public:
     }
     /*!
      * \brief Sets the temperature
-     *
      * @param value Value to be stored
      */
     void setTemperature(Scalar value)
@@ -239,7 +272,6 @@ public:
     }
     /*!
      * \brief Sets phase pressure
-     *
      * \param phaseIdx the index of the phase
      * @param value Value to be stored
      */
diff --git a/dumux/material/fluidstates/CMakeLists.txt b/dumux/material/fluidstates/CMakeLists.txt
index a2ba880bb2..7dfb611501 100644
--- a/dumux/material/fluidstates/CMakeLists.txt
+++ b/dumux/material/fluidstates/CMakeLists.txt
@@ -1,11 +1,12 @@
 
 #install headers
 install(FILES
+2p2c.hh
 compositional.hh
 immiscible.hh
 isothermalimmiscible.hh
-nonequilibriumenergy.hh
 nonequilibrium.hh
+nonequilibriumenergy.hh
 nonequilibriummass.hh
 pressureoverlay.hh
 saturationoverlay.hh
diff --git a/dumux/material/fluidstates/compositional.hh b/dumux/material/fluidstates/compositional.hh
index 86999c562f..79d5198363 100644
--- a/dumux/material/fluidstates/compositional.hh
+++ b/dumux/material/fluidstates/compositional.hh
@@ -18,7 +18,7 @@
  *****************************************************************************/
 /*!
  * \file
- *
+ * \ingroup FluidStates
  * \brief Represents all relevant thermodynamic quantities of a
  *        multi-phase, multi-component fluid system assuming
  *        thermodynamic equilibrium.
diff --git a/dumux/material/fluidstates/immiscible.hh b/dumux/material/fluidstates/immiscible.hh
index 694ce45907..8688eb646f 100644
--- a/dumux/material/fluidstates/immiscible.hh
+++ b/dumux/material/fluidstates/immiscible.hh
@@ -18,7 +18,7 @@
  *****************************************************************************/
 /*!
  * \file
- *
+ * \ingroup FluidStates
  * \brief Represents all relevant thermodynamic quantities of a
  *        multi-phase fluid system assuming immiscibility and
  *        thermodynamic equilibrium.
@@ -60,37 +60,81 @@ public:
      * on thermodynamic equilibrium required)
      *****************************************************/
     /*!
-     * @copydoc CompositionalFluidState::saturation()
+     * \brief Returns the saturation \f$S_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The saturation is defined as the pore space occupied by the fluid divided by the total pore space:
+     *  \f[S_\alpha := \frac{\phi \mathcal{V}_\alpha}{\phi \mathcal{V}}\f]
+     *
+     * \param phaseIdx the index of the phase
      */
     Scalar saturation(int phaseIdx) const
     { return saturation_[phaseIdx]; }
 
     /*!
-     * @copydoc CompositionalFluidState::moleFraction()
+     * \brief Returns the molar fraction \f$x^\kappa_\alpha\f$ of the component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The molar fraction \f$x^\kappa_\alpha\f$ is defined as the ratio of the number of molecules
+     * of component \f$\kappa\f$ and the total number of molecules of the phase \f$\alpha\f$.
+     * They are set either 1 or 0 in a phase since this is an immiscible fluidstate.
+     * \param phaseIdx the index of the phase
+     * \param compIdx the index of the component
      */
     Scalar moleFraction(int phaseIdx, int compIdx) const
     { return (phaseIdx == compIdx)?1.0:0.0; }
 
     /*!
-     * @copydoc CompositionalFluidState::massFraction()
+     * \brief Returns the mass fraction \f$X^\kappa_\alpha\f$ of component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * They are set either 1 or 0 in a phase since this is an immiscible fluidstate.
+     *
+     * \param phaseIdx the index of the phase
+     * \param compIdx the index of the component
      */
     Scalar massFraction(int phaseIdx, int compIdx) const
     { return (phaseIdx == compIdx)?1.0:0.0; }
 
     /*!
-     * @copydoc CompositionalFluidState::averageMolarMass()
+     * \brief The average molar mass \f$\overline M_\alpha\f$ of phase \f$\alpha\f$ in \f$\mathrm{[kg/mol]}\f$
+     *
+     * The average molar mass is the mean mass of a mole of the
+     * fluid at current composition. It is defined as the sum of the
+     * component's molar masses weighted by the current mole fraction:
+     * \f[\mathrm{ \overline M_\alpha = \sum_\kappa M^\kappa x_\alpha^\kappa}\f]
+     *
+     * Since this is an immiscible fluidstate we simply consider the molarMass of the
+     * pure component/phase.
      */
     Scalar averageMolarMass(int phaseIdx) const
     { return FluidSystem::molarMass(/*compIdx=*/phaseIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::molarity()
+     * \brief The molar concentration \f$c^\kappa_\alpha\f$ of component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[mol/m^3]}\f$
+     *
+     * This quantity is usually called "molar concentration" or just
+     * "concentration", but there are many other (though less common)
+     * measures for concentration.
+     *
+     * http://en.wikipedia.org/wiki/Concentration
      */
     Scalar molarity(int phaseIdx, int compIdx) const
     { return molarDensity(phaseIdx)*moleFraction(phaseIdx, compIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::fugacity()
+     * \brief The fugacity \f$f^\kappa_\alpha\f$ of component \f$\kappa\f$
+     *  in fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa]}\f$
+     *
+     *  The fugacity is defined as:
+     *  \f$f_\alpha^\kappa := \Phi^\kappa_\alpha x^\kappa_\alpha p_\alpha \;,\f$
+     *  where \f$\Phi^\kappa_\alpha\f$ is the fugacity coefficient \cite reid1987 .
+     *  The physical meaning of fugacity becomes clear from the equation:
+     *       \f[f_\alpha^\kappa = p_\alpha \exp\left\{\frac{\zeta^\kappa_\alpha}{R T_\alpha} \right\} \;,\f]
+     *  where \f$\zeta^\kappa_\alpha\f$ represents the \f$\kappa\f$'s chemical
+     *  potential in phase \f$\alpha\f$, \f$R\f$ stands for the ideal gas constant,
+     *  and \f$T_\alpha\f$ for the absolute temperature of phase \f$\alpha\f$. Assuming thermal equilibrium,
+     *  there is a one-to-one mapping between a component's chemical potential
+     *  \f$\zeta^\kappa_\alpha\f$ and its fugacity \f$f^\kappa_\alpha\f$. In this
+     *  case chemical equilibrium can thus be expressed by:
+     *     \f[f^\kappa := f^\kappa_\alpha = f^\kappa_\beta\quad\forall \alpha, \beta\f]
      *
      * To avoid numerical issues with code that assumes miscibility,
      * we return a fugacity of 0 for components which do not mix with
@@ -107,7 +151,7 @@ public:
     }
 
     /*!
-     *  @copydoc CompositionalFluidState::fugacityCoefficient()
+     * \brief The fugacity coefficient \f$\Phi^\kappa_\alpha\f$ of component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$
      *
      * Since we assume immiscibility, the fugacity coefficients for
      * the components which are not miscible with the phase is
@@ -123,7 +167,7 @@ public:
     }
 
     /*!
-     * @copydoc CompositionalFluidState::partialPressure()
+     * \brief The partial pressure of a component in a phase \f$\mathrm{[Pa]}\f$
      *
      * To avoid numerical issues with code that assumes miscibility,
      * we return a partial pressure of 0 for components which do not mix with
@@ -138,50 +182,61 @@ public:
     }
 
     /*!
-     * @copydoc CompositionalFluidState::molarVolume()
+     * \brief The molar volume \f$v_{mol,\alpha}\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[m^3/mol]}\f$
      *
+     * This quantity is the inverse of the molar density.
      */
     Scalar molarVolume(int phaseIdx) const
     { return 1/molarDensity(phaseIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::density()
+     * \brief The mass density \f$\rho_\alpha\f$ of the fluid phase
+     *  \f$\alpha\f$ in \f$\mathrm{[kg/m^3]}\f$
      */
     Scalar density(int phaseIdx) const
     { return density_[phaseIdx]; }
 
     /*!
-     * @copydoc CompositionalFluidState::molarDensity()
+     * \brief The molar density \f$\rho_{mol,\alpha}\f$
+     *   of a fluid phase \f$\alpha\f$ in \f$\mathrm{[mol/m^3]}\f$
+     *
+     * The molar density is defined by the mass density \f$\rho_\alpha\f$ and the mean molar mass \f$\overline M_\alpha\f$:
+     *
+     * \f[\rho_{mol,\alpha} = \frac{\rho_\alpha}{\overline M_\alpha} \;.\f]
      */
     Scalar molarDensity(int phaseIdx) const
     { return density_[phaseIdx]/averageMolarMass(phaseIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::temperature()
+     * \brief The absolute temperature\f$T_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[K]}\f$
      */
     Scalar temperature(int phaseIdx) const
     { return temperature_; }
 
     /*!
-     *  @copydoc CompositionalFluidState::pressure()
+     * \brief The pressure \f$p_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa]}\f$
      */
     Scalar pressure(int phaseIdx) const
     { return pressure_[phaseIdx]; }
 
     /*!
-     * @copydoc CompositionalFluidState::enthalpy()
+     * \brief The specific enthalpy \f$h_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[J/kg]}\f$
      */
     Scalar enthalpy(int phaseIdx) const
     { return enthalpy_[phaseIdx]; }
 
     /*!
-     * @copydoc CompositionalFluidState::internalEnergy()
+     * \brief The specific internal energy \f$u_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[J/kg]}\f$
+     *
+     * The specific internal energy is defined by the relation:
+     *
+     * \f[u_\alpha = h_\alpha - \frac{p_\alpha}{\rho_\alpha}\f]
      */
     Scalar internalEnergy(int phaseIdx) const
     { return enthalpy_[phaseIdx] - pressure(phaseIdx)/density(phaseIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::viscosity()
+     * \brief The dynamic viscosity \f$\mu_\alpha\f$ of fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa s]}\f$
      */
     Scalar viscosity(int phaseIdx) const
     { return viscosity_[phaseIdx]; }
diff --git a/dumux/material/fluidstates/isothermalimmiscible.hh b/dumux/material/fluidstates/isothermalimmiscible.hh
index a028111d3d..ba5b0e7eae 100644
--- a/dumux/material/fluidstates/isothermalimmiscible.hh
+++ b/dumux/material/fluidstates/isothermalimmiscible.hh
@@ -18,7 +18,7 @@
  *****************************************************************************/
 /*!
  * \file
- *
+ * \ingroup FluidStates
  * \brief Represents all relevant thermodynamic quantities of a isothermal immiscible
  *        multi-phase fluid system
  */
@@ -56,37 +56,74 @@ public:
      * Generic access to fluid properties
      *****************************************************/
     /*!
-     * @copydoc CompositionalFluidState::saturation()
+     * \brief Returns the saturation \f$S_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The saturation is defined as the pore space occupied by the fluid divided by the total pore space:
+     *  \f[S_\alpha := \frac{\phi \mathcal{V}_\alpha}{\phi \mathcal{V}}\f]
+     *
+     * \param phaseIdx the index of the phase
      */
     Scalar saturation(int phaseIdx) const
     { return saturation_[phaseIdx]; }
 
     /*!
-     * @copydoc CompositionalFluidState::moleFraction()
+     * \brief Returns the molar fraction \f$x^\kappa_\alpha\f$ of the component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The molar fraction \f$x^\kappa_\alpha\f$ is defined as the ratio of the number of molecules
+     * of component \f$\kappa\f$ and the total number of molecules of the phase \f$\alpha\f$.
+     * They are set either 1 or 0 in a phase since this is an immiscible fluidstate.
+     * \param phaseIdx the index of the phase
+     * \param compIdx the index of the component
      */
     Scalar moleFraction(int phaseIdx, int compIdx) const
     { return (phaseIdx == compIdx)?1.0:0.0; }
 
     /*!
-     * @copydoc CompositionalFluidState::massFraction()
+     * \brief Returns the mass fraction \f$X^\kappa_\alpha\f$ of component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * They are set either 1 or 0 in a phase since this is an immiscible fluidstate.
+     *
+     * \param phaseIdx the index of the phase
+     * \param compIdx the index of the component
      */
     Scalar massFraction(int phaseIdx, int compIdx) const
     { return (phaseIdx == compIdx)?1.0:0.0; }
 
     /*!
-     * @copydoc CompositionalFluidState::averageMolarMass()
+     * \brief The average molar mass \f$\overline M_\alpha\f$ of phase \f$\alpha\f$ in \f$\mathrm{[kg/mol]}\f$
+     *
+     * The average molar mass is the mean mass of a mole of the
+     * fluid at current composition. It is defined as the sum of the
+     * component's molar masses weighted by the current mole fraction:
+     * \f[\mathrm{ \overline M_\alpha = \sum_\kappa M^\kappa x_\alpha^\kappa}\f]
+     *
+     * Since this is an immiscible fluidstate we simply consider the molarMass of the
+     * pure component/phase.
      */
     Scalar averageMolarMass(int phaseIdx) const
     { return FluidSystem::molarMass(/*compIdx=*/phaseIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::molarity()
+     * \brief The molar concentration \f$c^\kappa_\alpha\f$ of component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[mol/m^3]}\f$
+     *
+     * This quantity is usually called "molar concentration" or just
+     * "concentration", but there are many other (though less common)
+     * measures for concentration.
+     *
+     * http://en.wikipedia.org/wiki/Concentration
      */
     Scalar molarity(int phaseIdx, int compIdx) const
     { return molarDensity(phaseIdx)*moleFraction(phaseIdx, compIdx); }
 
     /*!
+     * \brief The fugacity \f$f^\kappa_\alpha\f$ of component \f$\kappa\f$
+     *  in fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa]}\f$
      * @copydoc ImmiscibleFluidState::fugacity()
+     * To avoid numerical issues with code that assumes miscibility,
+     * we return a fugacity of 0 for components which do not mix with
+     * the specified phase. (Actually it is undefined, but for finite
+     * fugacity coefficients, the only way to get components
+     * completely out of a phase is 0 to feed it zero fugacity.)
      */
     Scalar fugacity(int phaseIdx, int compIdx) const
     {
@@ -97,7 +134,12 @@ public:
     }
 
     /*!
-     * @copydoc ImmiscibleFluidState::fugacityCoefficient()
+     * \brief The fugacity coefficient \f$\Phi^\kappa_\alpha\f$ of component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$
+     *
+     * Since we assume immiscibility, the fugacity coefficients for
+     * the components which are not miscible with the phase is
+     * infinite. Beware that this will very likely break your code if
+     * you don't keep that in mind.
      */
     Scalar fugacityCoefficient(int phaseIdx, int compIdx) const
     {
@@ -108,19 +150,27 @@ public:
     }
 
     /*!
-     * @copydoc CompositionalFluidState::molarVolume()
+     * \brief The molar volume \f$v_{mol,\alpha}\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[m^3/mol]}\f$
+     *
+     * This quantity is the inverse of the molar density.
      */
     Scalar molarVolume(int phaseIdx) const
     { return 1/molarDensity(phaseIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::density()
+     * \brief The mass density \f$\rho_\alpha\f$ of the fluid phase
+     *  \f$\alpha\f$ in \f$\mathrm{[kg/m^3]}\f$
      */
     Scalar density(int phaseIdx) const
     { return density_[phaseIdx]; }
 
     /*!
-     * @copydoc CompositionalFluidState::molarDensity()
+     * \brief The molar density \f$\rho_{mol,\alpha}\f$
+     *   of a fluid phase \f$\alpha\f$ in \f$\mathrm{[mol/m^3]}\f$
+     *
+     * The molar density is defined by the mass density \f$\rho_\alpha\f$ and the mean molar mass \f$\overline M_\alpha\f$:
+     *
+     * \f[\rho_{mol,\alpha} = \frac{\rho_\alpha}{\overline M_\alpha} \;.\f]
      */
     Scalar molarDensity(int phaseIdx) const
     { return density_[phaseIdx]/averageMolarMass(phaseIdx); }
@@ -138,25 +188,30 @@ public:
     { return temperature_; }
 
     /*!
-     *  @copydoc CompositionalFluidState::pressure()
+     * \brief The pressure \f$p_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa]}\f$
      */
     Scalar pressure(int phaseIdx) const
     { return pressure_[phaseIdx]; }
 
     /*!
-     * @copydoc CompositionalFluidState::enthalpy()
+     * \brief The specific enthalpy \f$h_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[J/kg]}\f$
+     * This is not defined for an isothermal fluidstate.
      */
     Scalar enthalpy(int phaseIdx) const
     { DUNE_THROW(Dune::NotImplemented,"No enthalpy() function defined for isothermal systems!"); }
 
     /*!
-     * @copydoc CompositionalFluidState::internalEnergy()
+     * \brief The specific internal energy \f$u_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[J/kg]}\f$
+     *
+     * The specific internal energy is defined by the relation:
+     * \f[u_\alpha = h_\alpha - \frac{p_\alpha}{\rho_\alpha}\f]
+     * This is not defined for an isothermal fluidstate.
      */
     Scalar internalEnergy(int phaseIdx) const
     { DUNE_THROW(Dune::NotImplemented,"No internalEnergy() function defined for isothermal systems!"); }
 
     /*!
-     * @copydoc CompositionalFluidState::viscosity()
+     * \brief The dynamic viscosity \f$\mu_\alpha\f$ of fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa s]}\f$
      */
     Scalar viscosity(int phaseIdx) const
     { return viscosity_[phaseIdx]; }
diff --git a/dumux/material/fluidstates/nonequilibrium.hh b/dumux/material/fluidstates/nonequilibrium.hh
index 330206ae02..2b659ec139 100644
--- a/dumux/material/fluidstates/nonequilibrium.hh
+++ b/dumux/material/fluidstates/nonequilibrium.hh
@@ -18,7 +18,7 @@
  *****************************************************************************/
 /*!
  * \file
- *
+ * \ingroup FluidStates
  * \brief Represents all relevant thermodynamic quantities of a
  *        multi-phase, multi-component fluid system without using
  *        any assumptions.
@@ -68,20 +68,43 @@ public:
      * on thermodynamic equilibrium required)
      *****************************************************/
     /*!
-     * @copydoc Dumux::CompositionalFluidState::saturation()
+     * \brief Returns the saturation \f$S_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The saturation is defined as the pore space occupied by the fluid divided by the total pore space:
+     *  \f[S_\alpha := \frac{\phi \mathcal{V}_\alpha}{\phi \mathcal{V}}\f]
+     *
+     * \param phaseIdx the index of the phase
      */
     Scalar saturation(int phaseIdx) const
     { return saturation_[phaseIdx]; }
 
     /*!
-     * @copydoc Dumux::CompositionalFluidState::moleFraction()
+     * \brief Returns the molar fraction \f$x^\kappa_\alpha\f$ of the component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The molar fraction \f$x^\kappa_\alpha\f$ is defined as the ratio of the number of molecules
+     * of component \f$\kappa\f$ and the total number of molecules of the phase \f$\alpha\f$.
+     *
+     * \param phaseIdx the index of the phase
+     * \param compIdx the index of the component
      */
     Scalar moleFraction(int phaseIdx, int compIdx) const
     { return moleFraction_[phaseIdx][compIdx]; }
 
 
     /*!
-     * @copydoc Dumux::CompositionalFluidState::massFraction()
+     * \brief Returns the mass fraction \f$X^\kappa_\alpha\f$ of component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The mass fraction \f$X^\kappa_\alpha\f$ is defined as the weight of all molecules of a
+     * component divided by the total mass of the fluid phase. It is related with the component's mole fraction by means of the relation
+     *
+     * \f[X^\kappa_\alpha = x^\kappa_\alpha \frac{M^\kappa}{\overline M_\alpha}\;,\f]
+     *
+     * where \f$M^\kappa\f$ is the molar mass of component \f$\kappa\f$ and
+     * \f$\overline M_\alpha\f$ is the mean molar mass of a molecule of phase
+     * \f$\alpha\f$.
+     *
+     * \param phaseIdx the index of the phase
+     * \param compIdx the index of the component
      */
     Scalar massFraction(int phaseIdx, int compIdx) const
     {
@@ -95,67 +118,105 @@ public:
     }
 
     /*!
-     * @copydoc Dumux::CompositionalFluidState::averageMolarMass()
+     * \brief The average molar mass \f$\overline M_\alpha\f$ of phase \f$\alpha\f$ in \f$\mathrm{[kg/mol]}\f$
+     *
+     * The average molar mass is the mean mass of a mole of the
+     * fluid at current composition. It is defined as the sum of the
+     * component's molar masses weighted by the current mole fraction:
+     * \f[\mathrm{ \overline M_\alpha = \sum_\kappa M^\kappa x_\alpha^\kappa}\f]
      */
     Scalar averageMolarMass(int phaseIdx) const
     { return averageMolarMass_[phaseIdx]; }
 
     /*!
-     * @copydoc Dumux::CompositionalFluidState::molarity()
+     * \brief The molar concentration \f$c^\kappa_\alpha\f$ of component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[mol/m^3]}\f$
+     *
+     * This quantity is usually called "molar concentration" or just
+     * "concentration", but there are many other (though less common)
+     * measures for concentration.
+     *
+     * http://en.wikipedia.org/wiki/Concentration
      */
     Scalar molarity(int phaseIdx, int compIdx) const
     { return molarDensity(phaseIdx)*moleFraction(phaseIdx, compIdx); }
 
     /*!
-     * @copydoc Dumux::CompositionalFluidState::fugacityCoefficient()
+     * \brief The fugacity coefficient \f$\Phi^\kappa_\alpha\f$ of component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$
      */
     Scalar fugacityCoefficient(int phaseIdx, int compIdx) const
     { return fugacityCoefficient_[phaseIdx][compIdx]; }
 
     /*!
-     * @copydoc Dumux::CompositionalFluidState::fugacity()
+     * \brief The fugacity \f$f^\kappa_\alpha\f$ of component \f$\kappa\f$
+     *  in fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa]}\f$
+     *
+     *  The fugacity is defined as:
+     *  \f$f_\alpha^\kappa := \Phi^\kappa_\alpha x^\kappa_\alpha p_\alpha \;,\f$
+     *  where \f$\Phi^\kappa_\alpha\f$ is the fugacity coefficient \cite reid1987 .
+     *  The physical meaning of fugacity becomes clear from the equation:
+     *       \f[f_\alpha^\kappa = p_\alpha \exp\left\{\frac{\zeta^\kappa_\alpha}{R T_\alpha} \right\} \;,\f]
+     *  where \f$\zeta^\kappa_\alpha\f$ represents the \f$\kappa\f$'s chemical
+     *  potential in phase \f$\alpha\f$, \f$R\f$ stands for the ideal gas constant,
+     *  and \f$T_\alpha\f$ for the absolute temperature of phase \f$\alpha\f$. Assuming thermal equilibrium,
+     *  there is a one-to-one mapping between a component's chemical potential
+     *  \f$\zeta^\kappa_\alpha\f$ and its fugacity \f$f^\kappa_\alpha\f$. In this
+     *  case chemical equilibrium can thus be expressed by:
+     *     \f[f^\kappa := f^\kappa_\alpha = f^\kappa_\beta\quad\forall \alpha, \beta\f]
      */
     Scalar fugacity(int phaseIdx, int compIdx) const
     { return pressure_[phaseIdx]*fugacityCoefficient_[phaseIdx][compIdx]*moleFraction_[phaseIdx][compIdx]; }
 
     /*!
-     * @copydoc Dumux::CompositionalFluidState::molarVolume()
+     * \brief The molar volume \f$v_{mol,\alpha}\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[m^3/mol]}\f$
+     *
+     * This quantity is the inverse of the molar density.
      */
     Scalar molarVolume(int phaseIdx) const
     { return 1/molarDensity(phaseIdx); }
 
     /*!
-     * @copydoc Dumux::CompositionalFluidState::density()
+     * \brief The mass density \f$\rho_\alpha\f$ of the fluid phase
+     *  \f$\alpha\f$ in \f$\mathrm{[kg/m^3]}\f$
      */
     Scalar density(int phaseIdx) const
     { return density_[phaseIdx]; }
 
     /*!
-     * @copydoc Dumux::CompositionalFluidState::molarDensity()
+     * \brief The molar density \f$\rho_{mol,\alpha}\f$
+     *   of a fluid phase \f$\alpha\f$ in \f$\mathrm{[mol/m^3]}\f$
+     *
+     * The molar density is defined by the mass density \f$\rho_\alpha\f$ and the mean molar mass \f$\overline M_\alpha\f$:
+     *
+     * \f[\rho_{mol,\alpha} = \frac{\rho_\alpha}{\overline M_\alpha} \;.\f]
      */
     Scalar molarDensity(int phaseIdx) const
     { return density_[phaseIdx]/averageMolarMass(phaseIdx); }
 
 
     /*!
-     * @copydoc Dumux::CompositionalFluidState::temperature()
+     * \brief The absolute temperature\f$T_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[K]}\f$
      */
     Scalar temperature(int phaseIdx) const
     { return temperature_[phaseIdx]; }
 
     /*!
-     * @copydoc Dumux::CompositionalFluidState::pressure()
+     * \brief The pressure \f$p_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa]}\f$
      */
     Scalar pressure(int phaseIdx) const
     { return pressure_[phaseIdx]; }
+
     /*!
-     * @copydoc Dumux::CompositionalFluidState::enthalpy()
+     * \brief The specific enthalpy \f$h_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[J/kg]}\f$
      */
     Scalar enthalpy(int phaseIdx) const
     { return enthalpy_[phaseIdx]; }
 
     /*!
-     * @copydoc Dumux::CompositionalFluidState::internalEnergy()
+     * \brief The specific internal energy \f$u_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[J/kg]}\f$
+     *
+     * The specific internal energy is defined by the relation:
+     *
+     * \f[u_\alpha = h_\alpha - \frac{p_\alpha}{\rho_\alpha}\f]
      */
     Scalar internalEnergy(int phaseIdx) const
     {
@@ -164,7 +225,7 @@ public:
     }
 
     /*!
-     * @copydoc Dumux::CompositionalFluidState::viscosity()
+     * \brief The dynamic viscosity \f$\mu_\alpha\f$ of fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa s]}\f$
      */
     Scalar viscosity(int phaseIdx) const
     { return viscosity_[phaseIdx]; }
diff --git a/dumux/material/fluidstates/nonequilibriumenergy.hh b/dumux/material/fluidstates/nonequilibriumenergy.hh
index 3dd5b3a0ec..7ae3cc7ff1 100644
--- a/dumux/material/fluidstates/nonequilibriumenergy.hh
+++ b/dumux/material/fluidstates/nonequilibriumenergy.hh
@@ -18,7 +18,7 @@
  *****************************************************************************/
 /*!
  * \file
- *
+ * \ingroup FluidStates
  * \brief Represents all relevant thermodynamic quantities of a
  *        multi-phase, multi-component fluid system without using
  *        any assumptions.
@@ -70,8 +70,22 @@ public:
     { return fugacity(0, compIdx); }
 
     /*!
-     * @copydoc NonEquilibriumFluidState::fugacity()
-    */
+     * \brief The fugacity \f$f^\kappa_\alpha\f$ of component \f$\kappa\f$
+     *  in fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa]}\f$
+     *
+     *  The fugacity is defined as:
+     *  \f$f_\alpha^\kappa := \Phi^\kappa_\alpha x^\kappa_\alpha p_\alpha \;,\f$
+     *  where \f$\Phi^\kappa_\alpha\f$ is the fugacity coefficient \cite reid1987 .
+     *  The physical meaning of fugacity becomes clear from the equation:
+     *       \f[f_\alpha^\kappa = p_\alpha \exp\left\{\frac{\zeta^\kappa_\alpha}{R T_\alpha} \right\} \;,\f]
+     *  where \f$\zeta^\kappa_\alpha\f$ represents the \f$\kappa\f$'s chemical
+     *  potential in phase \f$\alpha\f$, \f$R\f$ stands for the ideal gas constant,
+     *  and \f$T_\alpha\f$ for the absolute temperature of phase \f$\alpha\f$. Assuming thermal equilibrium,
+     *  there is a one-to-one mapping between a component's chemical potential
+     *  \f$\zeta^\kappa_\alpha\f$ and its fugacity \f$f^\kappa_\alpha\f$. In this
+     *  case chemical equilibrium can thus be expressed by:
+     *     \f[f^\kappa := f^\kappa_\alpha = f^\kappa_\beta\quad\forall \alpha, \beta\f]
+     */
     Scalar fugacity(int phaseIdx, int compIdx) const
     {
         // Unfortunately throw does not work when triggered from a constructor
diff --git a/dumux/material/fluidstates/nonequilibriummass.hh b/dumux/material/fluidstates/nonequilibriummass.hh
index f1351c8d0e..5bbd5a7ed3 100644
--- a/dumux/material/fluidstates/nonequilibriummass.hh
+++ b/dumux/material/fluidstates/nonequilibriummass.hh
@@ -18,7 +18,7 @@
  *****************************************************************************/
 /*!
  * \file
- *
+ * \ingroup FluidStates
  * \brief Represents all relevant thermodynamic quantities of a
  *        multi-phase, multi-component fluid system without using
  *        any assumptions.
@@ -106,7 +106,7 @@ class NonEquilibriumMassFluidState
         return temperature_ ;
     }
 
-    /*!
+     /*!
       * \brief Retrieve all parameters from an arbitrary fluid
       *        state. The assign method from the parent class cannot be used, because here, we have only one temperature.
       * \param fs Fluidstate
@@ -134,8 +134,6 @@ class NonEquilibriumMassFluidState
 
      }
 
-
-
 private:
     Scalar temperature_;
 };
diff --git a/dumux/material/fluidstates/pressureoverlay.hh b/dumux/material/fluidstates/pressureoverlay.hh
index 18309fab90..b3380b7b31 100644
--- a/dumux/material/fluidstates/pressureoverlay.hh
+++ b/dumux/material/fluidstates/pressureoverlay.hh
@@ -18,7 +18,7 @@
  *****************************************************************************/
 /*!
  * \file
- *
+ * \ingroup FluidStates
  * \brief This is a fluid state which allows to set the fluid
  *        pressures and takes all other quantities from an other
  *        fluid state.
@@ -80,91 +80,151 @@ public:
      * on thermodynamic equilibrium required)
      *****************************************************/
     /*!
-     *  @copydoc CompositionalFluidState::saturation()
+     * \brief Returns the saturation \f$S_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The saturation is defined as the pore space occupied by the fluid divided by the total pore space:
+     *  \f[S_\alpha := \frac{\phi \mathcal{V}_\alpha}{\phi \mathcal{V}}\f]
+     *
+     * \param phaseIdx the index of the phase
      */
     Scalar saturation(int phaseIdx) const
     { return fs_->saturation(phaseIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::moleFraction()
+     * \brief Returns the molar fraction \f$x^\kappa_\alpha\f$ of the component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The molar fraction \f$x^\kappa_\alpha\f$ is defined as the ratio of the number of molecules
+     * of component \f$\kappa\f$ and the total number of molecules of the phase \f$\alpha\f$.
+     *
+     * \param phaseIdx the index of the phase
+     * \param compIdx the index of the component
      */
     Scalar moleFraction(int phaseIdx, int compIdx) const
     { return fs_->moleFraction(phaseIdx, compIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::massFraction()
+     * \brief Returns the mass fraction \f$X^\kappa_\alpha\f$ of component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The mass fraction \f$X^\kappa_\alpha\f$ is defined as the weight of all molecules of a
+     * component divided by the total mass of the fluid phase. It is related with the component's mole fraction by means of the relation
+     *
+     * \f[X^\kappa_\alpha = x^\kappa_\alpha \frac{M^\kappa}{\overline M_\alpha}\;,\f]
+     *
+     * where \f$M^\kappa\f$ is the molar mass of component \f$\kappa\f$ and
+     * \f$\overline M_\alpha\f$ is the mean molar mass of a molecule of phase
+     * \f$\alpha\f$.
+     *
+     * \param phaseIdx the index of the phase
+     * \param compIdx the index of the component
      */
     Scalar massFraction(int phaseIdx, int compIdx) const
     { return fs_->massFraction(phaseIdx, compIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::averageMolarMass()
+     * \brief The average molar mass \f$\overline M_\alpha\f$ of phase \f$\alpha\f$ in \f$\mathrm{[kg/mol]}\f$
+     *
+     * The average molar mass is the mean mass of a mole of the
+     * fluid at current composition. It is defined as the sum of the
+     * component's molar masses weighted by the current mole fraction:
+     * \f[\mathrm{ \overline M_\alpha = \sum_\kappa M^\kappa x_\alpha^\kappa}\f]
      */
     Scalar averageMolarMass(int phaseIdx) const
     { return fs_->averageMolarMass(phaseIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::molarity()
+     * \brief The molar concentration \f$c^\kappa_\alpha\f$ of component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[mol/m^3]}\f$
+     *
+     * This quantity is usually called "molar concentration" or just
+     * "concentration", but there are many other (though less common)
+     * measures for concentration.
+     *
+     * http://en.wikipedia.org/wiki/Concentration
      */
     Scalar molarity(int phaseIdx, int compIdx) const
     { return fs_->molarity(phaseIdx, compIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::fugacity()
+     * \brief The fugacity \f$f^\kappa_\alpha\f$ of component \f$\kappa\f$
+     *  in fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa]}\f$
+     *
+     *  The fugacity is defined as:
+     *  \f$f_\alpha^\kappa := \Phi^\kappa_\alpha x^\kappa_\alpha p_\alpha \;,\f$
+     *  where \f$\Phi^\kappa_\alpha\f$ is the fugacity coefficient \cite reid1987 .
+     *  The physical meaning of fugacity becomes clear from the equation:
+     *       \f[f_\alpha^\kappa = p_\alpha \exp\left\{\frac{\zeta^\kappa_\alpha}{R T_\alpha} \right\} \;,\f]
+     *  where \f$\zeta^\kappa_\alpha\f$ represents the \f$\kappa\f$'s chemical
+     *  potential in phase \f$\alpha\f$, \f$R\f$ stands for the ideal gas constant,
+     *  and \f$T_\alpha\f$ for the absolute temperature of phase \f$\alpha\f$. Assuming thermal equilibrium,
+     *  there is a one-to-one mapping between a component's chemical potential
+     *  \f$\zeta^\kappa_\alpha\f$ and its fugacity \f$f^\kappa_\alpha\f$. In this
+     *  case chemical equilibrium can thus be expressed by:
+     *     \f[f^\kappa := f^\kappa_\alpha = f^\kappa_\beta\quad\forall \alpha, \beta\f]
      */
     Scalar fugacity(int phaseIdx, int compIdx) const
     { return fs_->fugacity(phaseIdx, compIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::fugacityCoefficient()
+     * \brief The fugacity coefficient \f$\Phi^\kappa_\alpha\f$ of component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$
      */
     Scalar fugacityCoefficient(int phaseIdx, int compIdx) const
     { return fs_->fugacityCoefficient(phaseIdx, compIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::molarVolume()
+     * \brief The molar volume \f$v_{mol,\alpha}\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[m^3/mol]}\f$
+     *
+     * This quantity is the inverse of the molar density.
      */
     Scalar molarVolume(int phaseIdx) const
     { return fs_->molarVolume(phaseIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::density()
+     * \brief The mass density \f$\rho_\alpha\f$ of the fluid phase
+     *  \f$\alpha\f$ in \f$\mathrm{[kg/m^3]}\f$
      */
     Scalar density(int phaseIdx) const
     { return fs_->density(phaseIdx); }
 
     /*!
-     *@copydoc CompositionalFluidState::molarDensity()
+     * \brief The molar density \f$\rho_{mol,\alpha}\f$
+     *   of a fluid phase \f$\alpha\f$ in \f$\mathrm{[mol/m^3]}\f$
+     *
+     * The molar density is defined by the mass density \f$\rho_\alpha\f$ and the mean molar mass \f$\overline M_\alpha\f$:
+     *
+     * \f[\rho_{mol,\alpha} = \frac{\rho_\alpha}{\overline M_\alpha} \;.\f]
      */
     Scalar molarDensity(int phaseIdx) const
     { return fs_->molarDensity(phaseIdx); }
 
     /*!
-     * @copydoc CompositionalFluidState::temperature()
+     * \brief The absolute temperature\f$T_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[K]}\f$
      */
     Scalar temperature(int phaseIdx) const
     { return fs_->temperature(phaseIdx); }
 
     /*!
-     *  @copydoc CompositionalFluidState::pressure()
+     * \brief The pressure \f$p_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa]}\f$
      */
     Scalar pressure(int phaseIdx) const
     { return pressure_[phaseIdx]; }
 
     /*!
-     * @copydoc CompositionalFluidState::enthalpy()
+     * \brief The specific enthalpy \f$h_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[J/kg]}\f$
      */
     Scalar enthalpy(int phaseIdx) const
     { return fs_->enthalpy(phaseIdx); }
 
     /*!
-     *  @copydoc CompositionalFluidState::internalEnergy()
+     * \brief The specific internal energy \f$u_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[J/kg]}\f$
+     *
+     * The specific internal energy is defined by the relation:
+     *
+     * \f[u_\alpha = h_\alpha - \frac{p_\alpha}{\rho_\alpha}\f]
      */
     Scalar internalEnergy(int phaseIdx) const
     { return fs_->internalEnergy(phaseIdx); }
 
     /*!
-     *  @copydoc CompositionalFluidState::viscosity()
+     * \brief The dynamic viscosity \f$\mu_\alpha\f$ of fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa s]}\f$
      */
     Scalar viscosity(int phaseIdx) const
     { return fs_->viscosity(phaseIdx); }
diff --git a/dumux/material/fluidstates/pseudo1p2c.hh b/dumux/material/fluidstates/pseudo1p2c.hh
index b35650c7a0..77c04a7121 100644
--- a/dumux/material/fluidstates/pseudo1p2c.hh
+++ b/dumux/material/fluidstates/pseudo1p2c.hh
@@ -18,7 +18,7 @@
  *****************************************************************************/
 /*!
  * \file
- *
+ * \ingroup FluidStates
  * \brief Calculates phase state for a single phase but two-component state.
  */
 #ifndef DUMUX_PSEUDO1P2C_FLUID_STATE_HH
@@ -56,7 +56,13 @@ public:
 public:
     /*! \name Acess functions */
     //@{
-    /*!  @copydoc CompositionalFluidState::saturation()
+    /*!
+     * \brief Returns the saturation \f$S_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The saturation is defined as the pore space occupied by the fluid divided by the total pore space:
+     *  \f[S_\alpha := \frac{\phi \mathcal{V}_\alpha}{\phi \mathcal{V}}\f]
+     * This is set either to 1 or 0 depending on the phase presence.
+     * \param phaseIdx the index of the phase
      */
     Scalar saturation(int phaseIdx) const
     {
@@ -86,7 +92,7 @@ public:
     }
 
     /*!
-     *  @copydoc CompositionalFluidState::partialPressure()
+     * \brief The partial pressure of a component in a phase \f$\mathrm{[Pa]}\f$
      */
     Scalar partialPressure(int phaseIdx, int compIdx) const
     {
@@ -94,13 +100,14 @@ public:
         return pressure(phaseIdx)*moleFraction(phaseIdx, compIdx);
     }
 
-    /*!  @copydoc CompositionalFluidState::pressure()
+    /*!
+     * \brief The pressure \f$p_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa]}\f$
      */
     Scalar pressure(int phaseIdx) const
     { return pressure_[phaseIdx]; }
 
     /*!
-     *  @copydoc CompositionalFluidState::density()
+     * \brief Set the density of a phase \f$\mathrm{[kg / m^3]}\f$
      */
     Scalar density(int phaseIdx) const
     {
@@ -112,7 +119,18 @@ public:
     }
 
     /*!
-     *  @copydoc CompositionalFluidState::massFraction()
+     * \brief Returns the mass fraction \f$X^\kappa_\alpha\f$ of component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The mass fraction \f$X^\kappa_\alpha\f$ is defined as the weight of all molecules of a
+     * component divided by the total mass of the fluid phase. It is related with the component's mole fraction by means of the relation
+     *
+     * This is either set to 1 or 0 depending on the phase presence for the
+     * non-wetting phase in general.
+     * It is set to the mass fraction of water or 1-massFractionWater
+     * if the considered component is the main component of the wetting phase.
+     *
+     * \param phaseIdx the index of the phase
+     * \param compIdx the index of the component
      */
     Scalar massFraction(int phaseIdx, int compIdx) const
     {
@@ -133,7 +151,14 @@ public:
     }
 
     /*!
-     *  @copydoc CompositionalFluidState::moleFraction()
+     * \brief Returns the molar fraction \f$x^\kappa_\alpha\f$ of the component \f$\kappa\f$ in fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * This is either set to 1 or 0 depending on the phase presence for the
+     * non-wetting phase in general.
+     * It is set to the mole fraction of water or 1-moleFractionWater
+     * if the considered component is the main component of the wetting phase.
+     * \param phaseIdx the index of the phase
+     * \param compIdx the index of the component
      */
     Scalar moleFraction(int phaseIdx, int compIdx) const
     {
@@ -152,7 +177,7 @@ public:
     }
 
     /*!
-     *  @copydoc CompositionalFluidState::viscosity()
+     * \brief The dynamic viscosity \f$\mu_\alpha\f$ of fluid phase \f$\alpha\f$ in \f$\mathrm{[Pa s]}\f$
      */
     Scalar viscosity(int phaseIdx) const
     {
@@ -161,7 +186,12 @@ public:
     }
 
     /*!
-     *  @copydoc CompositionalFluidState::averageMolarMass()
+     * \brief The average molar mass \f$\overline M_\alpha\f$ of phase \f$\alpha\f$ in \f$\mathrm{[kg/mol]}\f$
+     *
+     * The average molar mass is the mean mass of a mole of the
+     * fluid at current composition. It is defined as the sum of the
+     * component's molar masses weighted by the current mole fraction:
+     * \f[\mathrm{ \overline M_\alpha = \sum_\kappa M^\kappa x_\alpha^\kappa}\f]
      */
     Scalar averageMolarMass(int phaseIdx) const
     {
@@ -169,7 +199,7 @@ public:
     }
 
     /*!
-     *  @copydoc CompositionalFluidState::enthalpy()
+     * \brief The specific enthalpy \f$h_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[J/kg]}\f$
      */
     Scalar enthalpy(int phaseIdx) const
     {
@@ -180,7 +210,11 @@ public:
     }
 
     /*!
-     *  @copydoc CompositionalFluidState::internalEnergy()
+     * \brief The specific internal energy \f$u_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[J/kg]}\f$
+     *
+     * The specific internal energy is defined by the relation:
+     *
+     * \f[u_\alpha = h_\alpha - \frac{p_\alpha}{\rho_\alpha}\f]
      */
     Scalar internalEnergy(int phaseIdx) const
     {
diff --git a/dumux/material/fluidstates/saturationoverlay.hh b/dumux/material/fluidstates/saturationoverlay.hh
index 30b576ca44..14b7236d46 100644
--- a/dumux/material/fluidstates/saturationoverlay.hh
+++ b/dumux/material/fluidstates/saturationoverlay.hh
@@ -18,7 +18,7 @@
  *****************************************************************************/
 /*!
  * \file
- *
+ * \ingroup FluidStates
  * \brief This is a fluid state which allows to set the fluid
  *        saturations and takes all other quantities from an other
  *        fluid state.
@@ -77,7 +77,12 @@ public:
      * on thermodynamic equilibrium required)
      *****************************************************/
     /*!
-     *  @copydoc CompositionalFluidState::saturation()
+     * \brief Returns the saturation \f$S_\alpha\f$ of a fluid phase \f$\alpha\f$ in \f$\mathrm{[-]}\f$.
+     *
+     * The saturation is defined as the pore space occupied by the fluid divided by the total pore space:
+     *  \f[S_\alpha := \frac{\phi \mathcal{V}_\alpha}{\phi \mathcal{V}}\f]
+     *
+     * \param phaseIdx the index of the phase
      */
     Scalar saturation(int phaseIdx) const
     { return saturation_[phaseIdx]; }
diff --git a/dumux/material/fluidstates/temperatureoverlay.hh b/dumux/material/fluidstates/temperatureoverlay.hh
index 576d0b8aee..b902ebccdb 100644
--- a/dumux/material/fluidstates/temperatureoverlay.hh
+++ b/dumux/material/fluidstates/temperatureoverlay.hh
@@ -18,7 +18,7 @@
  *****************************************************************************/
 /*!
  * \file
- *
+ * \ingroup FluidStates
  * \brief This is a fluid state which allows to set the fluid
  *        temperatures and takes all other quantities from an other
  *        fluid state.
-- 
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