diff --git a/dune/elasticity/common/nonlinearelasticityproblem.cc b/dune/elasticity/common/nonlinearelasticityproblem.cc
index 39fc4b5f740ffe3345656340906892ad6f218c4a..0694f0c01dcb6ea1c52116d30537e68d3ca1b325 100644
--- a/dune/elasticity/common/nonlinearelasticityproblem.cc
+++ b/dune/elasticity/common/nonlinearelasticityproblem.cc
@@ -10,17 +10,17 @@ void NonlinearElasticityProblem<VectorType, MatrixType, Basis>::assembleQP(const
 
     const Basis& basis = material_->basis();
 
-    GridFunctionPtr displace = std::make_shared<BasisGridFunction<Basis,VectorType> >(basis,iterate);A
+    GridFunctionPtr displace = std::make_shared<BasisGridFunction<Basis,VectorType> >(basis,iterate);
 
     // assemble quadratic term
     OperatorAssembler<Basis,Basis> globalAssembler(basis,basis);
-    globalAssembler.assemble(material_->secondDerivative(displace), A);
+    globalAssembler.assemble(material_->secondDerivative(displace), A_);
 
     // assemble linear term
     FunctionalAssembler<Basis> funcAssembler(basis);
-    funcAssembler.assemble(material_->firstDerivative(displace), f);
-    f -= *extForces_;
-    f *= -1;
+    funcAssembler.assemble(material_->firstDerivative(displace), f_);
+    f_ -= *extForces_;
+    f_ *= -1;
 }
 
 template <class VectorType, class MatrixType, class Basis>
@@ -94,11 +94,11 @@ typename VectorType::field_type NonlinearElasticityProblem<VectorType,MatrixType
 template <class VectorType, class MatrixType, class Basis>
 typename VectorType::field_type NonlinearElasticityProblem<VectorType,MatrixType, Basis>::modelDecrease(const VectorType& correction) const
 {
-    // the model decrease is simply <f,corr> - 0.5 <corr, H corr>
+    // the model decrease is simply -<f,corr> - 0.5 <corr, H corr>
     VectorType tmp(correction.size());
-    A.mv(correction, tmp);
+    A_.mv(correction, tmp);
 
-    return (f*correction) - 0.5 * (correction*tmp);
+    return (f_*correction) - 0.5 * (correction*tmp);
 }
 
 
diff --git a/dune/elasticity/common/nonlinearelasticityproblem.hh b/dune/elasticity/common/nonlinearelasticityproblem.hh
index 2a80781011b6a40f9577be989e40d6a8224f3581..f2da69b18d49ec981f0d9f814fa3a1c87710d151 100644
--- a/dune/elasticity/common/nonlinearelasticityproblem.hh
+++ b/dune/elasticity/common/nonlinearelasticityproblem.hh
@@ -44,9 +44,9 @@ public:
     field_type modelDecrease(const VectorType& correction) const;
 
     //! The quadratic part
-    MatrixType A;
+    MatrixType A_;
     //! The linear functional
-    VectorType f;
+    VectorType f_;
 
 private:
     //! The involved materials