diff --git a/dumux/material/fluidsystems/2pimmiscible.hh b/dumux/material/fluidsystems/2pimmiscible.hh
index 577b8f3ec75263930a2687b31c43a00ddeb8de66..9673242e13e371fcf0df6d397026fd6e0061a2bc 100644
--- a/dumux/material/fluidsystems/2pimmiscible.hh
+++ b/dumux/material/fluidsystems/2pimmiscible.hh
@@ -290,7 +290,7 @@ public:
      * \brief Calculate the fugacity coefficient \f$\mathrm{[-]}\f$ of an individual
      *        component in a fluid phase
      *
-     * The fugacity coefficient \f$\mathrm{\phi_\kappa_\alpha}\f$ is connected to the
+     * The fugacity coefficient \f$\mathrm{\phi^\kappa_\alpha}\f$ is connected to the
      * fugacity \f$\mathrm{f^\kappa_\alpha}\f$ and the component's mole
      * fraction \f$\mathrm{x^\kappa_\alpha}\f$ by means of the relation
      *
diff --git a/dumux/material/fluidsystems/base.hh b/dumux/material/fluidsystems/base.hh
index 1be0448426f9ea447f499f617e6397e8ad540b1e..fbd4b070ebc947fe5aa1caf884c43d2dfd96da7f 100644
--- a/dumux/material/fluidsystems/base.hh
+++ b/dumux/material/fluidsystems/base.hh
@@ -124,7 +124,7 @@ public:
      * \brief Calculate the fugacity coefficient \f$\mathrm{[-]}\f$ of an individual
      *        component in a fluid phase
      *
-     * The fugacity coefficient \f$\mathrm{\phi_\kappa_\alpha}\f$ is connected to the
+     * The fugacity coefficient \f$\mathrm{\phi^\kappa_\alpha}\f$ is connected to the
      * fugacity \f$\mathrm{f^\kappa_\alpha}\f$ and the component's mole
      * fraction \f$\mathrm{x^\kappa_\alpha}\f$ by means of the relation
      *