diff --git a/dumux/porousmediumflow/1p/model.hh b/dumux/porousmediumflow/1p/model.hh
index 9567ad7a05e361cfc788ab90d1972356b9d3c970..974f746043cb0f88a51e07d71992262c509be8e1 100644
--- a/dumux/porousmediumflow/1p/model.hh
+++ b/dumux/porousmediumflow/1p/model.hh
@@ -12,11 +12,20 @@
  * Single-phase, isothermal flow model, which uses a standard Darcy approach as the
  * equation for the conservation of momentum. For details on Darcy's law see dumux/flux/darcyslaw.hh.
  *
- * Furthermore, it solves the mass continuity equation:
+ * Furthermore, it solves the mass continuity equation
  * \f[
  \phi \frac{\partial \varrho}{\partial t} + \text{div} \left\lbrace
  - \varrho \frac{\textbf K}{\mu} \left( \textbf{grad}\, p -\varrho {\textbf g} \right) \right\rbrace = q,
  * \f]
+* where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ \varrho \f$ is the mass density,
+ * * \f$ \textbf{K} \f$ is the intrinsic permeability tensor,
+ * * \f$ \mu \f$ represents the dynamic viscosity,
+ * * \f$  p \f$ is the pressure,
+ * * \f$ \textbf{g} \f$ is the gravitational acceleration vector,
+ * * and \f$ q \f$ is a source or sink term.
+ *
  *
  * The model supports compressible as well as incompressible fluids.
  */
diff --git a/dumux/porousmediumflow/1pnc/model.hh b/dumux/porousmediumflow/1pnc/model.hh
index 74eab408b965aa7e4f68187a0bcbd2a7e3be95ba..e44629d578927dab000be18b306ad3f64d7016b2 100644
--- a/dumux/porousmediumflow/1pnc/model.hh
+++ b/dumux/porousmediumflow/1pnc/model.hh
@@ -17,7 +17,7 @@
  \f[
  \phi\frac{\partial \varrho}{\partial t} - \text{div} \left\{
    \varrho \frac{\textbf K}{\mu}  \left(\textbf{grad}\, p - \varrho {\textbf g} \right)
- \right\} = q \;,
+ \right\} = q.
  \f]
  *
  * The transport of the components \f$\kappa \in \{ w, a, ... \}\f$ is described by the following equation:
@@ -25,8 +25,19 @@
  \phi \frac{ \partial \varrho X^\kappa}{\partial t}
  - \text{div} \left\lbrace \varrho X^\kappa \frac{{\textbf K}}{\mu} \left( \textbf{grad}\, p -
  \varrho {\textbf g} \right)
- + \varrho D^\kappa_\text{pm} \textbf{grad} X^\kappa \right\rbrace = q.
+ + \varrho D^\kappa_\text{pm} \textbf{grad} X^\kappa \right\rbrace = q,
  \f]
+ *
+  * where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ \varrho \f$ is the mass density,
+ * * \f$ X^\kappa \f$ is the mass fraction of component \f$ \kappa \f$,
+ * * \f$ \textbf{K} \f$ is the intrinsic permeability tensor,
+ * * \f$ \mu \f$ represents the dynamic viscosity,
+ * * \f$ p \f$ is the pressure,
+ * * \f$ \textbf{g} \f$ is the gravitational acceleration vector,
+ * * \f$ {\bf D_{pm}^\kappa} \f$ is the diffusivity in the porous medium,
+ * * and \f$ q \f$ is a source or sink term.
  *
  * The model is able to use either mole or mass fractions. The property useMoles can be set to either true or false in the
  * problem file. Make sure that the according units are used in the problem setup. useMoles is set to true by default.
diff --git a/dumux/porousmediumflow/1pncmin/model.hh b/dumux/porousmediumflow/1pncmin/model.hh
index db3ff0612148ac0b338a9010592b05d2674b48a0..3c853041f9dfc8931a936858c071ab5f62d1a1cf 100644
--- a/dumux/porousmediumflow/1pncmin/model.hh
+++ b/dumux/porousmediumflow/1pncmin/model.hh
@@ -16,33 +16,56 @@
 * For details on Darcy's law see dumux/flux/darcyslaw.hh.
 *
 * By inserting Darcy's law into the equations for the conservation of the
-* components, one gets one transport equation for each component
+* components, one gets one transport equation for each component,
 * \f[
  \frac{\partial ( \varrho_f X^\kappa \phi  )}
 {\partial t} -  \text{div} \left\{ \varrho_f X^\kappa
 \frac{k_{r}}{\mu} \mathbf{K}
 (\text{grad}\, p - \varrho_{f}  \mathbf{g}) \right\}
 - \text{div} \left\{{\bf D_{pm}^\kappa} \varrho_{f} \text{grad}\, X^\kappa \right\}
--  q_\kappa = 0 \qquad \kappa \in \{w, a,\cdots \}
+-  q_\kappa = 0 \qquad \kappa \in \{w, a,\cdots \},
 * \f]
+* where:
+* * \f$ \phi \f$ is the  porosity,
+* * \f$ \varrho_f \f$ is the mass density of the fluid,
+* * \f$ X^\kappa \f$ is the mass fraction of component \f$ \kappa \f$ in the fluid,
+* * \f$ k_{r} \f$ is the relative permeability,
+* * \f$ \mu \f$ represents the dynamic viscosity,
+* * \f$ \mathbf{K} \f$ is the intrinsic permeability tensor,
+* * \f$ p \f$ is the pressure,
+* * \f$ \mathbf{g} \f$ is the gravitational acceleration vector,
+* * \f$ {\bf D_{pm}^\kappa} \f$ is the diffusivity in the porous medium,
+* * \f$ q_\kappa \f$ is a source or sink term.
 *
 * The solid or mineral phases are assumed to consist of a single component.
-* Their mass balance consist only of a storage and a source term:
+* Their mass balance consists of only a storage and a source term,
 * \f[
- \frac{\partial ( \varrho_\lambda \phi_\lambda )} {\partial t} = q_\lambda
+ \frac{\partial ( \varrho_\lambda \phi_\lambda )} {\partial t} = q_\lambda,
 * \f]
-*
+* where:
+* * \f$ \varrho_\lambda\f$ represents the mass density of the solid phase,
+* * \f$ \phi_\lambda \f$ is the porosity of the solid,
+* * \f$ q_\lambda \f$ is a source or sink term representing.
 *
 * The primary variables are the pressure \f$p\f$ and the mole fractions of the
 * dissolved components \f$x^k\f$. The primary variable of the solid phases is the volume
 * fraction
-\f$\phi_\lambda = \frac{V_\lambda}{V_{total}}\f$.
+\f$\phi_\lambda = \frac{V_\lambda}{V_{total}}\f$,
+*
+* where:
+* * \f$ V_\lambda \f$ is the volume of phase \f$ \lambda \f$,
+* * \f$ V_{\text{total}} \f$ is the total volume of the system.
 *
 * The source an sink terms link the mass balances of the n-transported component to the
 * solid phases. The porosity \f$\phi\f$ is updated according to the reduction of the initial
 * (or solid-phase-free porous medium) porosity \f$\phi_0\f$ by the accumulated volume
-* fractions of the solid phases:
-* \f$ \phi = \phi_0 - \sum (\phi_\lambda)\f$
+* fractions of the solid phases,
+* \f$ \phi = \phi_0 - \sum (\phi_\lambda),\f$
+*
+* where:
+* * \f$ \phi \f$ represents the remaining porosity in the system,
+* * \f$ \phi_0 \f$ is the initial porosity,
+* * \f$ \phi_\lambda \f$ denotes the volume fraction of phase \f$ \lambda \f$.
 * Additionally, the permeability is updated depending on the current porosity.
 */
 
diff --git a/dumux/porousmediumflow/2p/model.hh b/dumux/porousmediumflow/2p/model.hh
index 534154f545a283f95ef7567f12c8520541e5e43c..ea762c5ec9bf7a793e4255aa0a8b64bad6137300 100644
--- a/dumux/porousmediumflow/2p/model.hh
+++ b/dumux/porousmediumflow/2p/model.hh
@@ -21,8 +21,18 @@
  -
  \text{div} \left\{
  \varrho_\alpha \frac{k_{r\alpha}}{\mu_\alpha} \mathbf{K} \left(\textbf{grad}\, p_\alpha - \varrho_{\alpha} \mathbf{g} \right)
- \right\} - q_\alpha = 0 \;,
+ \right\} - q_\alpha = 0,
  \f]
+ *where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ S_\alpha \f$ represents the saturation of phase \f$ \alpha \f$,
+ * * \f$ \varrho_\alpha \f$ is the mass density of phase \f$ \alpha \f$,
+ * * \f$ k_{r\alpha} \f$ is the relative permeability of phase \f$ \alpha \f$,
+ * * \f$ \mu_\alpha \f$ is the dynamic viscosity of phase \f$ \alpha \f$,
+ * * \f$ \mathbf{K} \f$ is the intrinsic permeability tensor,
+ * * \f$ p_\alpha \f$ is the pressure of phase \f$ \alpha \f$,
+ * * \f$ \mathbf{g} \f$ is the gravitational acceleration vector,
+ * * \f$ q_\alpha \f$ is a source or sink term.
  *
  * By using constitutive relations for the capillary pressure \f$p_c =
  * p_n - p_w\f$ and relative permeability \f$k_{r\alpha}\f$ and taking
diff --git a/dumux/porousmediumflow/2p1c/model.hh b/dumux/porousmediumflow/2p1c/model.hh
index 2ad2fad615434184658f43f1ef79f1570f5b30e8..aadf24482aae9322d7a2e33bd1b1e84bf8b2fd51 100644
--- a/dumux/porousmediumflow/2p1c/model.hh
+++ b/dumux/porousmediumflow/2p1c/model.hh
@@ -24,8 +24,18 @@
  * phase mass, one gets
  \f[
 \phi \frac{\partial\ \sum_\alpha (\rho_\alpha S_\alpha)}{\partial t} \\-\sum \limits_ \alpha \text{div} \left \{\rho_\alpha \frac{k_{r\alpha}}{\mu_\alpha}
-\mathbf{K} (\mathbf{grad}p_\alpha - \rho_\alpha \mathbf{g}) \right \} -q^w =0
+\mathbf{K} (\mathbf{grad}p_\alpha - \rho_\alpha \mathbf{g}) \right \} -q^w =0,
  \f]
+ * where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ S_\alpha \f$ represents  the  saturation of phase \f$ \alpha \f$,
+ * * \f$ \rho_\alpha \f$ is the mass density of phase \f$ \alpha \f$,
+ * * \f$ k_{r\alpha} \f$ is the relative permeability of phase \f$ \alpha \f$,
+ * * \f$ \mu_\alpha \f$ is the dynamic viscosity of phase \f$ \alpha \f$,
+ * * \f$ \mathbf{K} \f$ is the intrinsic permeability tensor,
+ * * \f$ p_\alpha \f$ is the pressure of phase \f$  \alpha \f$,
+ * * \f$ \mathbf{g} \f$ is the gravitational acceleration vector,
+ * * \f$ q^w \f$ is a source or sink term.
  *
  * By using constitutive relations for the capillary pressure \f$p_c =
  * p_n - p_w\f$ and relative permeability \f$k_{r\alpha}\f$ and taking
diff --git a/dumux/porousmediumflow/2p2c/model.hh b/dumux/porousmediumflow/2p2c/model.hh
index fab70a8dc390f2a21e0ef9f37f1172e27cf4d664..4b388d2ccbce567017f5033a6f4e3fd512f460d7 100644
--- a/dumux/porousmediumflow/2p2c/model.hh
+++ b/dumux/porousmediumflow/2p2c/model.hh
@@ -14,22 +14,30 @@
  * \f$\kappa \in \{ \kappa_w, \kappa_n \}\f$, where \f$\kappa_w\f$ and \f$\kappa_n\f$ are
  * the main components of the wetting and nonwetting phases, respectively.
  * The governing equations are the mass or the mole conservation equations of the two components,
- * depending on the property <tt>UseMoles</tt>. The mass balance equations are given as:
+ * depending on the property <tt>UseMoles</tt>. The mass balance equations are given as
  * \f[
    \phi \frac{\partial (\sum_\alpha \rho_\alpha X_\alpha^\kappa S_\alpha)}{\partial t}
    - \sum_\alpha \text{div} \left\{ \rho_\alpha X_\alpha^\kappa v_\alpha \right\}
    - \sum_\alpha \text{div} \mathbf{F}_{\mathrm{diff, mass}, \alpha}^\kappa
-   - \sum_\alpha q_\alpha^\kappa = 0 \qquad \kappa \in \{\kappa_w, \kappa_n\} \, , \alpha \in \{w, n\},
+   - \sum_\alpha q_\alpha^\kappa = 0 \qquad \kappa \in \{\kappa_w, \kappa_n\} \, , \alpha \in \{w, n\}.
    \f]
- * using the mass fractions \f$X_\alpha^\kappa\f$ and the mass densities \f$\rho_\alpha\f$, while
- * the mole balance equations use the mole fractions \f$x_\alpha^\kappa\f$ and molar
- * densities \f$\varrho_{m, \alpha}\f$:
+ * The mole balance is given as
  * \f[
    \phi \frac{\partial (\sum_\alpha \varrho_{m, \alpha} x_\alpha^\kappa S_\alpha)}{\partial t}
    + \sum_\alpha \text{div} \left\{ \varrho_{m, \alpha} x_\alpha^\kappa v_\alpha \right\}
    + \sum_\alpha \text{div} \mathbf{F}_{\mathrm{diff, mole}, \alpha}^\kappa
-   - \sum_\alpha q_\alpha^\kappa = 0 \qquad \kappa \in \{\kappa_w, \kappa_n\} \, , \alpha \in \{w, n\}.
+   - \sum_\alpha q_\alpha^\kappa = 0 \qquad \kappa \in \{\kappa_w, \kappa_n\} \, , \alpha \in \{w, n\},
    \f]
+    * where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ S_\alpha \f$ represents the saturation of phase \f$ \alpha \f$,
+ * * \f$ \rho_\alpha \f$ is the mass density of phase \f$ \alpha \f$,
+ * * \f$ X_\alpha^\kappa \f$ is the mass fraction of component \f$ \kappa \f$ in phase  \f$ \alpha \f$,
+ * * \f$ x_\alpha^\kappa \f$ is the mole fraction of component \f$ \kappa \f$ in phase    \f$ \alpha \f$,
+ * * \f$ v_\alpha \f$ is the velocity of phase \f$ \alpha \f$,
+ * * \f$ \mathbf{F}_{\mathrm{diff, mass}, \alpha}^\kappa \f$ represents the diffusive  mass flux of component \f$ \kappa \f$ in phase \f$ \alpha \f$,
+ * * \f$ q_\alpha^\kappa \f$ is a source or sink term.
+ *
  * Boundary conditions and sources have to be defined by the user in the corresponding
  * units. The default setting for the property <tt>UseMoles</tt> can be found in the 2pnc model.
  *
diff --git a/dumux/porousmediumflow/2pnc/model.hh b/dumux/porousmediumflow/2pnc/model.hh
index 2f06005de08e273ab6527db1940b71e96cbfa322..c4eeee6390be88cf38a4df96750a5a591d6e8ced 100644
--- a/dumux/porousmediumflow/2pnc/model.hh
+++ b/dumux/porousmediumflow/2pnc/model.hh
@@ -18,7 +18,7 @@
  * For details on Darcy's law see dumux/flux/darcyslaw.hh.
  *
  * By inserting Darcy's law into the equations for the conservation of the
- * components, one gets one transport equation for each component
+ * components, one gets one transport equation for each component,
  * \f{eqnarray*}{
  * && \frac{\partial (\sum_\alpha \varrho_\alpha X_\alpha^\kappa \phi S_\alpha )}
  * {\partial t}
@@ -28,13 +28,27 @@
  * \nonumber \\ \nonumber \\
  *   &-& \sum_\alpha \text{div} \left\{{\bf D_{\alpha, pm}^\kappa} \varrho_{\alpha} \text{grad}\, X^\kappa_{\alpha} \right\}
  * - \sum_\alpha q_\alpha^\kappa = 0 \qquad \kappa \in \{w, a,\cdots \} \, ,
- * \alpha \in \{w, g\}
+ * \alpha \in \{w, g\},
  * \f}
+ * where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ S_\alpha \f$ represents the saturation of phase \f$ \alpha \f$,
+ * * \f$ \rho_\alpha \f$ is the mass density of phase \f$ \alpha \f$,
+ * * \f$ X_\alpha^\kappa \f$ is the mass fraction of component \f$ \kappa \f$ in phase  \f$ \alpha \f$,
+ * * \f$ x_\alpha^\kappa \f$ is the mole fraction of component \f$ \kappa \f$ in phase    \f$ \alpha \f$,
+ * * \f$ v_\alpha \f$ is the velocity of phase \f$ \alpha \f$,
+ * * \f$ {\bf D_{\alpha, pm}^\kappa} \f$ is the diffusivity of component \f$ \kappa \f$  in phase \f$ \alpha \f$,
+ * * \f$ q_\alpha^\kappa \f$ is a source or sink term.
  *
  * The solid or mineral phases are assumed to consist of a single component.
- * Their mass balance consist only of a storage and a source term:
+ * Their mass balance consists of only a storage and a source term,
  *  \f$\frac{\partial \varrho_\lambda \phi_\lambda )} {\partial t}
- *  = q_\lambda\f$
+ *  = q_\lambda,\f$
+ *
+ * where:
+ * * \f$ \varrho_\lambda \f$ is the mass density of the solid phase \f$ \lambda \f$,
+ * * \f$ \phi_\lambda \f$ is the porosity of the solid,
+ * * \f$ q_\lambda \f$ is a source or sink term.
  *
  * By using constitutive relations for the capillary pressure \f$p_c =
  * p_n - p_w\f$ and relative permeability \f$k_{r\alpha}\f$ and taking
diff --git a/dumux/porousmediumflow/2pncmin/model.hh b/dumux/porousmediumflow/2pncmin/model.hh
index af3b475b279164f48fc5fdeffd201c934527e591..ed403351ba2a42759479d7ff8fc0a796e5ee78ec 100644
--- a/dumux/porousmediumflow/2pncmin/model.hh
+++ b/dumux/porousmediumflow/2pncmin/model.hh
@@ -18,7 +18,7 @@
  * For details on Darcy's law see dumux/flux/darcyslaw.hh.
  *
  * By inserting Darcy's law into the equations for the conservation of the
- * components, one gets one transport equation for each component
+ * components, one gets one transport equation for each component,
  * \f{eqnarray*}{
  * && \frac{\partial (\sum_\alpha \varrho_\alpha X_\alpha^\kappa \phi S_\alpha )}
  * {\partial t}
@@ -28,13 +28,28 @@
  * \nonumber \\ \nonumber \\
  *   &-& \sum_\alpha \text{div} \left\{{\bf D_{\alpha, pm}^\kappa} \varrho_{\alpha} \text{grad}\, X^\kappa_{\alpha} \right\}
  * - \sum_\alpha q_\alpha^\kappa = 0 \qquad \kappa \in \{w, a,\cdots \} \, ,
- * \alpha \in \{w, g\}
+ * \alpha \in \{w, g\},
  * \f}
  *
+ * where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ S_\alpha \f$ represents the saturation of phase \f$ \alpha \f$,
+ * * \f$ \rho_\alpha \f$ is the mass density of phase \f$ \alpha \f$,
+ * * \f$ X_\alpha^\kappa \f$ is the mass fraction of component \f$ \kappa \f$ in phase  \f$ \alpha \f$,
+ * * \f$ x_\alpha^\kappa \f$ is the mole fraction of component \f$ \kappa \f$ in phase    \f$ \alpha \f$,
+ * * \f$ v_\alpha \f$ is the velocity of phase \f$ \alpha \f$,
+ * * \f$ {\bf D_{\alpha, pm}^\kappa} \f$ is the diffusivity of component \f$ \kappa \f$  in phase \f$ \alpha \f$,
+ * * \f$ q_\alpha^\kappa \f$ is a source or sink term.
+ *
  * The solid or mineral phases are assumed to consist of a single component.
- * Their mass balance consist only of a storage and a source term:
+ * Their mass balance consists of only a storage and a source term,
  *  \f$\frac{\partial ( \varrho_\lambda \phi_\lambda )} {\partial t}
- *  = q_\lambda\f$
+ *  = q_\lambda,\f$
+ *
+ * where:
+ * * \f$ \varrho_\lambda \f$  mass density of the solid phase \f$ \lambda \f$,
+ * * \f$ \phi_\lambda \f$ is the porosity of the solid,
+ * * \f$ q_\lambda \f$ is a source or sink term.
  *
  * By using constitutive relations for the capillary pressure \f$p_c =
  * p_n - p_w\f$ and relative permeability \f$k_{r\alpha}\f$ and taking
diff --git a/dumux/porousmediumflow/3p/model.hh b/dumux/porousmediumflow/3p/model.hh
index 9416a6b37d914f38ced9e758d0b7e8684a1878a9..93355b96a1044ce7cbb6988848e7ee96e039bfc3 100644
--- a/dumux/porousmediumflow/3p/model.hh
+++ b/dumux/porousmediumflow/3p/model.hh
@@ -22,8 +22,18 @@
  -
  \text{div} \left\{
  \varrho_\alpha \frac{k_{r\alpha}}{\mu_\alpha} \mathbf{K} \left(\textbf{grad}\, p_\alpha - \varrho_{\alpha} \mathbf{g} \right)
- \right\} - q_\alpha = 0 \;.
+ \right\} - q_\alpha = 0,
  \f]
+ * where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ S_\alpha \f$ represents the saturation of phase \f$ \alpha \f$,
+ * * \f$ \varrho_\alpha \f$ is the mass density of phase \f$ \alpha \f$,
+ * * \f$ k_{r\alpha} \f$ is the relative permeability of phase \f$ \alpha \f$,
+ * * \f$ \mu_\alpha \f$ is the dynamic viscosity of phase \f$ \alpha \f$,
+ * * \f$ \mathbf{K} \f$ is the intrinsic permeability tensor,
+ * * \f$ p_\alpha \f$ is the pressure of phase \f$ \alpha \f$,
+ * * \f$ \mathbf{g} \f$ is the gravitational acceleration vector,
+ * * \f$ q_\alpha \f$ is a source or sink term.
  *
  * The model uses commonly applied auxiliary conditions like
  * \f$S_w + S_n + S_g = 1\f$ for the saturations.
diff --git a/dumux/porousmediumflow/3p3c/model.hh b/dumux/porousmediumflow/3p3c/model.hh
index ca7c8add70f6512ede88cab7e25ca2effc26d51d..4896a2b9ba917a56e06c7304df2700fe37e11ef3 100644
--- a/dumux/porousmediumflow/3p3c/model.hh
+++ b/dumux/porousmediumflow/3p3c/model.hh
@@ -28,8 +28,18 @@
  \nonumber \\
  && - \sum\limits_\alpha \text{div} \left\{ D_\text{pm}^\kappa \frac{1}{M_{\kappa}} \varrho_{\alpha}
  \textbf{grad} X^\kappa_{\alpha} \right\}
- - q^\kappa = 0 \qquad \forall \kappa , \; \forall \alpha
+ - q^\kappa = 0 \qquad \forall \kappa , \; \forall \alpha,
  \f}
+ * where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ S_\alpha \f$ represents the saturation of phase \f$ \alpha \f$,
+ * * \f$ \rho_\alpha \f$ is the mass density of phase \f$ \alpha \f$,
+ * * \f$ X_\alpha^\kappa \f$ is the mass fraction of component \f$ \kappa \f$ in phase  \f$ \alpha \f$,
+ * * \f$ x_\alpha^\kappa \f$ is the mole fraction of component \f$ \kappa \f$ in phase    \f$ \alpha \f$,
+ * * \f$ v_\alpha \f$ is the velocity of phase \f$ \alpha \f$,
+ * * \f$ {\bf D_{\alpha, pm}^\kappa} \f$ is the diffusivity of component \f$ \kappa \f$  in phase \f$ \alpha \f$,
+ * * \f$ M_\kappa \f$ is the molar mass of component \f$ \kappa \f$
+ * * \f$ q_\alpha^\kappa \f$ is a source or sink term.
  *
  * Note that these balance equations are molar.
  *
diff --git a/dumux/porousmediumflow/3pwateroil/model.hh b/dumux/porousmediumflow/3pwateroil/model.hh
index 397b2007f6c98dbb8af14cbce644e0202d582f8f..3a167f89f3ebb7a0028258e853b6a9e015dece2e 100644
--- a/dumux/porousmediumflow/3pwateroil/model.hh
+++ b/dumux/porousmediumflow/3pwateroil/model.hh
@@ -29,9 +29,20 @@
  \nonumber \\
  && - \sum\limits_\alpha \text{div} \left\{ D_\text{pm}^\kappa \varrho_\alpha \frac{1}{M_\kappa}
  \textbf{grad} X^\kappa_{\alpha} \right\}
- - q^\kappa = 0 \qquad \forall \kappa , \; \forall \alpha
+ - q^\kappa = 0 \qquad \forall \kappa , \; \forall \alpha,
  \f}
  *
+ * where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ S_\alpha \f$ represents the saturation of phase \f$ \alpha \f$,
+ * * \f$ \rho_\alpha \f$ is the mass density of phase \f$ \alpha \f$,
+ * * \f$ X_\alpha^\kappa \f$ is the mass fraction of component \f$ \kappa \f$ in phase  \f$ \alpha \f$,
+ * * \f$ x_\alpha^\kappa \f$ is the mole fraction of component \f$ \kappa \f$ in phase    \f$ \alpha \f$,
+ * * \f$ v_\alpha \f$ is the velocity of phase \f$ \alpha \f$,
+ * * \f$ {\bf D_{\alpha, pm}^\kappa} \f$ is the diffusivity of component \f$ \kappa \f$  in phase \f$ \alpha \f$,
+ * * \f$ M_\kappa \f$ is the molar mass of component \f$ \kappa \f$
+ * * \f$ q_\alpha^\kappa \f$ is a source or sink term.
+ *
  * Note that these balance equations are molar.
  *
  * The model uses commonly applied auxiliary conditions like
diff --git a/dumux/porousmediumflow/mineralization/model.hh b/dumux/porousmediumflow/mineralization/model.hh
index 2577e9874d0204fd2eceb1de83a54c918971ffd9..d23ae48e6b9edd807bb9057729a3f57107bca782 100644
--- a/dumux/porousmediumflow/mineralization/model.hh
+++ b/dumux/porousmediumflow/mineralization/model.hh
@@ -12,8 +12,15 @@
  *        components.
  *
  * The solid or mineral phases are assumed to consist of a single component.
- * Their mass balance consist only of a storage and a source term:
- * \f$\frac{\partial ( \varrho_\lambda \phi_\lambda )} {\partial t} = q_\lambda\f$
+ * Their mass balance consists of only a storage and a source term,
+ * \f[
+ * \frac{\partial ( \varrho_\lambda \phi_\lambda )} {\partial t} = q_\lambda,
+ * \f]
+ *
+ * where:
+ * * \f$ \varrho_\lambda \f$ is the mass density of the solid phase \f$ \lambda \f$,
+ * * \f$ \phi_\lambda \f$ is the porosity of the solid,
+ * * \f$ q_\lambda \f$ is a source or sink term.
  */
 
 #ifndef DUMUX_MINERALIZATION_MODEL_HH
diff --git a/dumux/porousmediumflow/mpnc/model.hh b/dumux/porousmediumflow/mpnc/model.hh
index 8ff3a7249be66a0eddf1727993f58fc751b35a64..f3ea0e7504450c50134441a7a20471e8b8b5b5c0 100644
--- a/dumux/porousmediumflow/mpnc/model.hh
+++ b/dumux/porousmediumflow/mpnc/model.hh
@@ -22,7 +22,7 @@
  *
  * By inserting this into the equations for the conservation of the
  * mass of each component, one gets one mass-continuity equation for
- * each component \f$\kappa\f$
+ * each component \f$\kappa\f$,
  * \f[
  \sum_{\kappa} \left(
     \phi \frac{\partial \left(\varrho_\alpha x_\alpha^\kappa S_\alpha\right)}{\partial t}
@@ -35,10 +35,21 @@
     \right)
     = q^\kappa
     \f]
- * with \f$\overline M_\alpha\f$ being the average molar mass of the
+ * with \f$\overline M_\alpha\f$ being the average molar mass of
  * phase \f$\alpha\f$: \f[ \overline M_\alpha = \sum_\kappa M^\kappa
  * \; x_\alpha^\kappa \f]
  *
+ * Additionally:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ S_\alpha \f$ represents the saturation of phase \f$ \alpha \f$,
+ * * \f$ \rho_\alpha \f$ is the mass density of phase \f$ \alpha \f$,
+ * * \f$ X_\alpha^\kappa \f$ is the mass fraction of component \f$ \kappa \f$ in phase  \f$ \alpha \f$,
+ * * \f$ x_\alpha^\kappa \f$ is the mole fraction of component \f$ \kappa \f$ in phase    \f$ \alpha \f$,
+ * * \f$ v_\alpha \f$ is the velocity of phase \f$ \alpha \f$,
+ * * \f$ {\bf D_{\alpha, pm}^\kappa} \f$ is the diffusivity of component \f$ \kappa \f$  in phase \f$ \alpha \f$,
+ * * \f$ \overline M_\alpha \f$ is the average molar mass of phase \f$ \alpha \f$
+ * * \f$ q_\alpha^\kappa \f$ is a source or sink term.
+ *
  * For the missing \f$M\f$ model assumptions, the model assumes that
  * if a fluid phase is not present, the sum of the mole fractions of
  * this fluid phase is smaller than \f$1\f$, i.e.
diff --git a/dumux/porousmediumflow/nonisothermal/model.hh b/dumux/porousmediumflow/nonisothermal/model.hh
index b04d686674d223e97920c95de4269fad8a0920ff..7d4593ac2bcb1efaa4463e26066392d2337474dc 100644
--- a/dumux/porousmediumflow/nonisothermal/model.hh
+++ b/dumux/porousmediumflow/nonisothermal/model.hh
@@ -17,7 +17,7 @@
  *
  * For the energy balance, local thermal equilibrium is assumed. This
  * results in one energy conservation equation for the porous solid
- * matrix and the fluids:
+ * matrix and the fluids,
  \f{align*}{
  \phi \frac{\partial \sum_\alpha \varrho_\alpha u_\alpha S_\alpha}{\partial t}
  & +
@@ -30,12 +30,25 @@
  \left( \textbf{grad}\,p_\alpha - \varrho_\alpha \mathbf{g} \right)
  \right\} \\
     & - \text{div} \left(\lambda_{pm} \textbf{grad} \, T \right)
-    - q^h = 0.
+    - q^h = 0,
  \f}
- * where \f$h_\alpha\f$ is the specific enthalpy of a fluid phase
- * \f$\alpha\f$ and \f$u_\alpha = h_\alpha -
- * p_\alpha/\varrho_\alpha\f$ is the specific internal energy of the
- * phase.
+ * where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ S_\alpha \f$ represents the saturation of phase \f$ \alpha \f$,
+ * * \f$ \rho_\alpha \f$ is the mass density of phase \f$ \alpha \f$,
+ * * \f$ h_\alpha \f$ is the specific enthalpy of phase  \f$ \alpha \f$,
+ * * \f$ u_\alpha \f$ is the specific internal energy of phase \f$ \alpha \f$,
+ * * \f$ \lambda_{pm}\f$ is the heat conductivity in the porous medium,
+ * * \f$ T \f$ is the temperature,
+ * * \f$ \rho_s \f$ is the mass density of the solid phase,
+ * * \f$ c_s \f$ is the heat capacity of the solid,
+ * * \f$ k_{r\alpha} \f$ is the relative permeability of phase \f$ \alpha \f$,
+ * * \f$ \mu_\alpha \f$ is the dynamic viscosity of phase \f$ \alpha \f$,
+ * * \f$ \mathbf{K} \f$ is the intrinsic permeability tensor,
+ * * \f$ p_\alpha \f$ is the pressure of phase \f$ \alpha \f$,
+ * * \f$ \mathbf{g} \f$ is the gravitational acceleration vector,
+ * * \f$ q^h \f$ is a source or sink term.
+ *
  */
 
 #ifndef DUMUX_NONISOTHERMAL_MODEL_HH
diff --git a/dumux/porousmediumflow/richards/model.hh b/dumux/porousmediumflow/richards/model.hh
index af9151801da9f7a9bbffeb1309122ef8a99a8db4..e1f00351fa61de68a19517c568d7363e058be614 100644
--- a/dumux/porousmediumflow/richards/model.hh
+++ b/dumux/porousmediumflow/richards/model.hh
@@ -16,13 +16,14 @@
  -
  \text{div} \left\lbrace
  \varrho_w \frac{k_{rw}}{\mu_w} \; \mathbf{K} \;
- \left( \text{\textbf{grad}}
+ \left( \textbf{grad}
  p_w - \varrho_w \textbf{g}
  \right)
  \right\rbrace
  =
  q_w,
  \f]
+ *
  * is frequently used to
  * approximate the water distribution above the groundwater level.
  *
@@ -32,21 +33,24 @@
  -
  \text{div} \left\lbrace
  \varrho_\alpha \frac{k_{r\alpha}}{\mu_\alpha}\; \mathbf{K} \;
- \left( \text{\textbf{grad}}
+ \left(\textbf{grad}
  p_\alpha - \varrho_\alpha \textbf{g}
  \right)
  \right\rbrace
  =
  q_\alpha,
  \f]
- * where \f$\alpha \in \{w, n\}\f$ is the fluid phase,
- * \f$\kappa \in \{ w, a \}\f$ are the components,
- * \f$\rho_\alpha\f$ is the fluid density, \f$S_\alpha\f$ is the fluid
- * saturation, \f$\phi\f$ is the porosity of the soil,
- * \f$k_{r\alpha}\f$ is the relative permeability for the fluid,
- * \f$\mu_\alpha\f$ is the fluid's dynamic viscosity, \f$\mathbf{K}\f$ is the
- * intrinsic permeability, \f$p_\alpha\f$ is the fluid pressure and
- * \f$g\f$ is the potential of the gravity field.
+ *
+ * where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ S_\alpha \f$ represents the saturation of phase \f$ \alpha \f$,
+ * * \f$ \varrho_\alpha \f$ is the mass density of phase \f$ \alpha \f$,
+ * * \f$ k_{r\alpha} \f$ is the relative permeability of phase \f$ \alpha \f$,
+ * * \f$ \mu_\alpha \f$ is the dynamic viscosity of phase \f$ \alpha \f$,
+ * * \f$ \mathbf{K} \f$ is the intrinsic permeability tensor,
+ * * \f$ p_\alpha \f$ is the pressure of phase \f$ \alpha \f$,
+ * * \f$ \mathbf{g} \f$ is the gravitational acceleration vector,
+ * * \f$ q_\alpha \f$ is a source or sink term.
  *
  * In contrast to the full two-phase model, the Richards model assumes
  * gas as the nonwetting fluid and that it exhibits a much lower
diff --git a/dumux/porousmediumflow/richardsextended/model.hh b/dumux/porousmediumflow/richardsextended/model.hh
index 91ae346ebb53756a11c8d61c0acbecd756ba38fe..4d76a3039a82b2ac994934b4c7b00b41833e6273 100644
--- a/dumux/porousmediumflow/richardsextended/model.hh
+++ b/dumux/porousmediumflow/richardsextended/model.hh
@@ -27,6 +27,20 @@
  =
  q_w,
  \f]
+ * where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ S_w \f$ represents the saturation of the wetting-phase,
+ * * \f$ \varrho_w \f$ is the mass density of the wetting phase,
+ * * \f$ \varrho_n \f$ is the mass density of the non-wetting phase,
+ * * \f$ k_{rw} \f$ is the relative permeability of the wetting phase,
+ * * \f$ \mu_w \f$ is the dynamic viscosity of the wetting phase,
+ * * \f$ \mathbf{K} \f$ is the intrinsic permeability tensor,
+ * * \f$ p_w \f$ is the pressure of the wetting phase,
+ * * \f$ \mathbf{g} \f$ is the gravitational acceleration vector,
+ * * \f$ \bf D_{n,pm}^{w} \f$ is the diffusivity of water in the non-wetting phase,
+ * * \f$ X_n^w \f$ is the mass fraction of water in the non-wetting phase,
+ * * \f$ q_w \f$ is a source or sink term in the wetting phase,
+ *
  * is frequently used to
  * approximate the water distribution above the groundwater level.
  *
@@ -43,14 +57,17 @@
  =
  q_\alpha,
  \f]
- * where \f$\alpha \in \{w, n\}\f$ is the fluid phase,
- * \f$\kappa \in \{ w, a \}\f$ are the components,
- * \f$\rho_\alpha\f$ is the fluid density, \f$S_\alpha\f$ is the fluid
- * saturation, \f$\phi\f$ is the porosity of the soil,
- * \f$k_{r\alpha}\f$ is the relative permeability for the fluid,
- * \f$\mu_\alpha\f$ is the fluid's dynamic viscosity, \f$\mathbf{K}\f$ is the
- * intrinsic permeability, \f$p_\alpha\f$ is the fluid pressure and
- * \f$g\f$ is the potential of the gravity field.
+ *
+ * where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ S_\alpha \f$ represents the saturation of phase \f$ \alpha \f$,
+ * * \f$ \varrho_\alpha \f$ is the mass density of phase \f$ \alpha \f$,
+ * * \f$ k_{r\alpha} \f$ is the relative permeability of phase \f$ \alpha \f$,
+ * * \f$ \mu_\alpha \f$ is the dynamic viscosity of phase \f$ \alpha \f$,
+ * * \f$ \mathbf{K} \f$ is the intrinsic permeability tensor,
+ * * \f$ p_\alpha \f$ is the pressure of phase \f$ \alpha \f$,
+ * * \f$ \mathbf{g} \f$ is the gravitational acceleration vector,
+ * * \f$ q_\alpha \f$ is a source or sink term.
  *
  * In contrast to the full two-phase model, the Richards model assumes
  * gas as the nonwetting fluid and that it exhibits a much lower
diff --git a/dumux/porousmediumflow/richardsnc/model.hh b/dumux/porousmediumflow/richardsnc/model.hh
index 7cd5c9475fd099a10043721526f7e4fe1d03d5bf..b6768784636caac922eb25e69596e7069c1aa14c 100644
--- a/dumux/porousmediumflow/richardsnc/model.hh
+++ b/dumux/porousmediumflow/richardsnc/model.hh
@@ -20,8 +20,21 @@
  \nonumber \\ \nonumber \\
     &-& \sum_w \text{div} \left\{{\bf D_{w, pm}^\kappa} \varrho_{w} \text{grad}\, X^\kappa_{w} \right\}
  - \sum_w q_w^\kappa = 0 \qquad \kappa \in \{w, a,\cdots \} \, ,
- w \in \{w, g\}
+ w \in \{w, g\},
  \f}
+ * where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ S_w \f$ represents the saturation of the wetting phase,
+ * * \f$ \varrho_w \f$ is the mass density of the wetting phase,
+ * * \f$ k_{rw} \f$ is the relative permeability of the wetting phase,
+ * * \f$ \mu_w \f$ is the dynamic viscosity of the wetting phase,
+ * * \f$ \mathbf{K} \f$ is the intrinsic permeability tensor,
+ * * \f$ p_w \f$ is the pressure of the wetting phase,
+ * * \f$ \mathbf{g} \f$ is the gravitational acceleration vector,
+ * * \f$ \bf D_{w,pm}^{k} \f$ is the diffusivity of component \f$ \kappa \f$ in the wetting phase,
+ * * \f$ X_w^k \f$ is the mass fraction of component \f$ \kappa \f$ in the wetting phase,
+ * * \f$ q_w \f$ is a source or sink term in the wetting phase,
+ *
  * is frequently used to
  * approximate the water distribution above the groundwater level.
  *
diff --git a/dumux/porousmediumflow/solidenergy/model.hh b/dumux/porousmediumflow/solidenergy/model.hh
index b1ad4448de8f17e1ccf9b01370f1472db2c20159..0ab596483652b9c7abe625167975d520a86379de 100644
--- a/dumux/porousmediumflow/solidenergy/model.hh
+++ b/dumux/porousmediumflow/solidenergy/model.hh
@@ -15,8 +15,14 @@
    \frac{ \partial n c_p \varrho T}{\partial t}
    - \text{div} \left\lbrace \lambda_\text{pm} \textbf{grad} T \right\rbrace = q,
  \f]
- * where \f$n\f$ is the volume fraction of the conducting material, \f$c_p\f$ its specific heat capacity,
- * \f$\varrho\f$ its density, \f$T\f$ the temperature, and \f$\lambda\f$ the heat conductivity of the porous solid.
+ * where:
+ * * \f$ n \f$  represents volume fraction of the conducting material,
+ * * \f$ c_p \f$ is the specific heat capacity at constant pressure,
+ * * \f$ \varrho \f$ is the mass density,
+ * * \f$ \lambda_\text{pm} \f$ is the heat conductivity in the  porous medium,
+ * * \f$ T \f$ is the temperature,
+ * * \f$ q \f$ is the heat source term.
+ *
 */
 
 #ifndef DUMUX_SOLID_ENERGY_MODEL_HH
diff --git a/dumux/porousmediumflow/tracer/model.hh b/dumux/porousmediumflow/tracer/model.hh
index 9278a68dc97d630aac1a4ff36d11f9e7c767ba0a..c9b4242c29cdb6380f1ce877ff35574bcf68357f 100644
--- a/dumux/porousmediumflow/tracer/model.hh
+++ b/dumux/porousmediumflow/tracer/model.hh
@@ -21,8 +21,15 @@
  \f[
  \phi \frac{ \partial \varrho X^\kappa}{\partial t}
  - \text{div} \left\lbrace \varrho X^\kappa {\textbf v_f}
- + \varrho D^\kappa_\text{pm} \textbf{grad} X^\kappa \right\rbrace = q.
+ + \varrho D^\kappa_\text{pm} \textbf{grad} X^\kappa \right\rbrace = q,
  \f]
+* where:
+ * * \f$ \phi \f$ is the porosity of the porous medium,
+ * * \f$ \varrho \f$ is the mass density,
+ * * \f$ X^\kappa \f$ is the mass fraction of component \f$ \kappa \f$,
+ * * \f$ \textbf{v}_f \f$ is the velocity of the fluid,
+ * * \f$ {\bf D_{pm}^\kappa} \f$ is the diffusivity in the porous medium,
+ * * \f$ q \f$ is a source or sink term.
  *
  * The model is able to use either mole or mass fractions. The property useMoles can be set to either true or false in the
  * problem file. Make sure that the according units are used in the problem setup. useMoles is set to true by default.