diff --git a/include/GDerivative.hpp b/include/GDerivative.hpp
index 8ffbdc6..f09156d 100644
--- a/include/GDerivative.hpp
+++ b/include/GDerivative.hpp
@@ -39,7 +39,7 @@ class GDerivative {
 
     // I/O friends
     friend std::ostream& operator<<(std::ostream& os, const GDerivative& dx);
-    friend GLog&         operator<<(GLog& os,         const GDerivative& dx);
+    friend GLog&         operator<<(GLog& log,        const GDerivative& dx);
 
 public:
 
diff --git a/src/model/GModelRadialShell.cpp b/src/model/GModelRadialShell.cpp
index 2e958d8..0ac4e63 100644
--- a/src/model/GModelRadialShell.cpp
+++ b/src/model/GModelRadialShell.cpp
@@ -634,10 +634,10 @@ void GModelRadialShell::free_members(void)
  *          \sqrt{1-\cos 2 {\tt m\_theta\_in}}}{2 \sqrt{2}} +
  *    \frac{1+\cos 2 {\tt m\_theta\_out}}{4} \ln \left(
  *          \frac{\sqrt{2} \cos {\tt m\_theta\_out}}
- *               {\sqrt{2} + \sqrt{1 - \cos 2 {\tt m\_theta\_out}}} -
+ *               {\sqrt{2} + \sqrt{1 - \cos 2 {\tt m\_theta\_out}}} \right) -
  *    \frac{1+\cos 2 {\tt m\_theta\_in}}{4} \ln \left(
  *          \frac{\sqrt{2} \cos {\tt m\_theta\_in}}
- *               {\sqrt{2} + \sqrt{1 - \cos 2 {\tt m\_theta\_in}}}\f]
+ *               {\sqrt{2} + \sqrt{1 - \cos 2 {\tt m\_theta\_in}}} \right)\f]
  ***************************************************************************/
 void GModelRadialShell::update() const
 {