diff --git a/programs/Hadrons/Graph.hpp b/programs/Hadrons/Graph.hpp
index 5f71f31b..78b43452 100644
--- a/programs/Hadrons/Graph.hpp
+++ b/programs/Hadrons/Graph.hpp
@@ -726,7 +726,7 @@ std::vector<std::vector<T>> Graph<T>::allTopoSort(void)
 }
 
 // build depedency matrix from topological sorts ///////////////////////////////
-// complexity: can be V!
+// complexity: something like O(V^2*log(V!))
 template <typename T>
 std::map<T, std::map<T, bool>>
 makeDependencyMatrix(const std::vector<std::vector<T>> &topSort)
diff --git a/programs/Hadrons/Module.cc b/programs/Hadrons/Module.cc
index 70fcd79f..6669a861 100644
--- a/programs/Hadrons/Module.cc
+++ b/programs/Hadrons/Module.cc
@@ -32,7 +32,7 @@ using namespace QCD;
 using namespace Hadrons;
 
 /******************************************************************************
- *                           Module implementation                            *
+ *                       ModuleBase implementation                            *
  ******************************************************************************/
 // constructor /////////////////////////////////////////////////////////////////
 ModuleBase::ModuleBase(const std::string name)
diff --git a/programs/Hadrons/Module.hpp b/programs/Hadrons/Module.hpp
index 7260eee8..c2bebd93 100644
--- a/programs/Hadrons/Module.hpp
+++ b/programs/Hadrons/Module.hpp
@@ -50,8 +50,9 @@ public:\
 static mod##ModuleRegistrar mod##ModuleRegistrarInstance;
 
 /******************************************************************************
- *                                 Module                                     *
+ *                            Module class                                    *
  ******************************************************************************/
+// base class
 class ModuleBase
 {
 public:
@@ -77,8 +78,7 @@ private:
     Environment &env_;
 };
 
-typedef Serializable NoPar;
-
+// derived class, templating the parameter class
 template <typename P>
 class Module: public ModuleBase
 {
@@ -98,6 +98,12 @@ private:
     P par_;
 };
 
+// no parameter type
+typedef Serializable NoPar;
+
+/******************************************************************************
+ *                           Template implementation                          *
+ ******************************************************************************/
 template <typename P>
 Module<P>::Module(const std::string name)
 : ModuleBase(name)
diff --git a/programs/Hadrons/Modules/MQuark.cc b/programs/Hadrons/Modules/MQuark.cc
index 3a0e27f8..ced6d362 100644
--- a/programs/Hadrons/Modules/MQuark.cc
+++ b/programs/Hadrons/Modules/MQuark.cc
@@ -93,11 +93,9 @@ void MQuark::execute(void)
             {
                 PropToFerm(tmp, fullSrc, s, c);
                 InsertSlice(source, tmp, 0, 0);
-                InsertSlice(source, tmp, Ls_ - 1, 0);
-                axpby_ssp_pplus(source, 0., source, 1., source,
-                                0, 0);
-                axpby_ssp_pminus(source, 0., source, 1., source,
-                                 Ls_ - 1, Ls_ - 1);
+                InsertSlice(source, tmp, Ls_-1, 0);
+                axpby_ssp_pplus(source, 0., source, 1., source, 0, 0);
+                axpby_ssp_pminus(source, 0., source, 1., source, Ls_-1, Ls_-1);
             }
         }
         // source conversion for 5D sources