diff --git a/corsika/detail/framework/geometry/QuantityVector.inl b/corsika/detail/framework/geometry/QuantityVector.inl
index 2ca24ee5a4a9c080276731e9652f7b03202a82ec..c7f9457b98dc0935c710f6d93fef6c53aab69f56 100644
--- a/corsika/detail/framework/geometry/QuantityVector.inl
+++ b/corsika/detail/framework/geometry/QuantityVector.inl
@@ -17,8 +17,8 @@
 namespace corsika {
 
   template <typename TDimension>
-  inline typename QuantityVector<TDimension>::quantity_type QuantityVector<TDimension>::
-  operator[](size_t const index) const {
+  inline typename QuantityVector<TDimension>::quantity_type
+  QuantityVector<TDimension>::operator[](size_t const index) const {
     return quantity_type(phys::units::detail::magnitude_tag, eigenVector_[index]);
   }
 
@@ -128,7 +128,7 @@ namespace corsika {
   }
 
   template <typename TDimension>
-  inline auto& QuantityVector<TDimension>::operator-() const {
+  inline auto QuantityVector<TDimension>::operator-() const {
     return QuantityVector<TDimension>(-eigenVector_);
   }
 
diff --git a/corsika/detail/framework/geometry/Vector.inl b/corsika/detail/framework/geometry/Vector.inl
index 352eb8b3095ddec2221c1af41dc8f71b499746e2..93907b944206f64364c254473739aa324f9c6aeb 100644
--- a/corsika/detail/framework/geometry/Vector.inl
+++ b/corsika/detail/framework/geometry/Vector.inl
@@ -194,7 +194,7 @@ namespace corsika {
   }
 
   template <typename TDimension>
-  inline auto& Vector<TDimension>::operator-() const {
+  inline auto Vector<TDimension>::operator-() const {
     return Vector<TDimension>(BaseVector<TDimension>::getCoordinateSystem(),
                               -BaseVector<TDimension>::getQuantityVector());
   }
diff --git a/corsika/framework/geometry/QuantityVector.hpp b/corsika/framework/geometry/QuantityVector.hpp
index d9199dc57490bea7c0204c6256eddc7d4f80ef8c..ac7afc51e96e6a0cc4a4a59b8102c3accbb0c476 100644
--- a/corsika/framework/geometry/QuantityVector.hpp
+++ b/corsika/framework/geometry/QuantityVector.hpp
@@ -89,7 +89,7 @@ namespace corsika {
 
     auto& operator-=(QuantityVector<TDimension> const& pQVec);
 
-    auto& operator-() const;
+    auto operator-() const;
 
     auto normalized() const;
 
diff --git a/corsika/framework/geometry/Vector.hpp b/corsika/framework/geometry/Vector.hpp
index fec720e4df43f33acb09aa536b6d6b482087cf5d..2a4b34a196a9363fc87926daeb9d5f5fcdb86076 100644
--- a/corsika/framework/geometry/Vector.hpp
+++ b/corsika/framework/geometry/Vector.hpp
@@ -131,7 +131,7 @@ namespace corsika {
 
     auto& operator-=(Vector<TDimension> const& pVec);
 
-    auto& operator-() const;
+    auto operator-() const;
 
     auto normalized() const;