diff --git a/dumux/freeflow/stokes/stokesfluxvariables.hh b/dumux/freeflow/stokes/stokesfluxvariables.hh
index 864299844e0da459d83c400eb42f78ac028f6468..6ffd16f5b789ca3f6afa507ad799934d71a12137 100644
--- a/dumux/freeflow/stokes/stokesfluxvariables.hh
+++ b/dumux/freeflow/stokes/stokesfluxvariables.hh
@@ -189,21 +189,21 @@ public:
     { return pressureAtIP_; }
 
     /*!
-     * \brief Return the mass density \f$\mathrm{[kg/m^3]}\f$ at the integration
+     * \brief Return the mass density \f$ \mathrm{[kg/m^3]} \f$ at the integration
      *        point.
      */
     Scalar densityAtIP() const
     { return densityAtIP_; }
 
     /*!
-     * \brief Return the viscosity \f$\mathrm{[m^2/s]}\f$ at the integration
+     * \brief Return the viscosity \f$ \mathrm{[m^2/s]} \f$ at the integration
      *        point.
      */
     Scalar viscosityAtIP() const
     { return viscosityAtIP_; }
 
     /*!
-     * \brief Return the normal velocity \f$\mathrm{[m/s]}\f$ at the integration
+     * \brief Return the normal velocity \f$ \mathrm{[m/s]} \f$ at the integration
      *        point.
      */
     Scalar normalVelocityAtIP() const
diff --git a/dumux/freeflow/stokes/stokesvolumevariables.hh b/dumux/freeflow/stokes/stokesvolumevariables.hh
index 9b24c94d5a84ab1819a9a97001566415883e3fa0..7f3d0f0579c85b184e18dbf93983d4c74dedb79f 100644
--- a/dumux/freeflow/stokes/stokesvolumevariables.hh
+++ b/dumux/freeflow/stokes/stokesvolumevariables.hh
@@ -162,7 +162,7 @@ public:
     { return fluidState_.temperature(phaseIdx); }
 
     /*!
-     * \brief Returns the viscosity \f$\mathrm{[m^2/s]}\f$ of the fluid in
+     * \brief Returns the viscosity \f$ \mathrm{[m^2/s]} \f$ of the fluid in
      *        the sub-control volume.
      */
     Scalar viscosity() const