diff --git a/lib/Physics/CorrelatorFitter.cpp b/lib/Physics/CorrelatorFitter.cpp
index d48699f..c997272 100644
--- a/lib/Physics/CorrelatorFitter.cpp
+++ b/lib/Physics/CorrelatorFitter.cpp
@@ -23,6 +23,9 @@
 using namespace std;
 using namespace Latan;
 
+/******************************************************************************
+ *                           Correlator models                                *
+ ******************************************************************************/
 DoubleModel CorrelatorModels::makeExpModel(const Index nState)
 {
     DoubleModel mod;
@@ -224,6 +227,10 @@ DVec CorrelatorModels::parameterGuess(const DMatSample &corr,
     return init;
 }
 
+/******************************************************************************
+ *                      CorrelatorFitter implementation                       *
+ ******************************************************************************/
+// constructors ////////////////////////////////////////////////////////////////
 CorrelatorFitter::CorrelatorFitter(const DMatSample &corr)
 {
     setCorrelator(corr);
@@ -234,6 +241,7 @@ CorrelatorFitter::CorrelatorFitter(const std::vector<DMatSample> &corr)
     setCorrelators(corr);
 }
 
+// access //////////////////////////////////////////////////////////////////////
 XYSampleData & CorrelatorFitter::data(void)
 {
     return *data_;
@@ -294,7 +302,7 @@ void CorrelatorFitter::setCorrelation(const bool isCorrelated, const Index i,
     data_->assumeYYCorrelated(isCorrelated, i, j);
 }
 
-DMat CorrelatorFitter::getVarianceMatrix(void)
+DMat CorrelatorFitter::getVarianceMatrix(void) const
 {
     return data_->getFitVarMat();
 }
@@ -305,6 +313,7 @@ void CorrelatorFitter::setThinning(const Index thinning, const Index i)
     refreshRanges();
 }
 
+// fit functions ///////////////////////////////////////////////////////////////
 SampleFitResult CorrelatorFitter::fit(Minimizer &minimizer, const DVec &init)
 {
     vector<Minimizer *> vecPt = {&minimizer};
@@ -325,6 +334,7 @@ SampleFitResult CorrelatorFitter::fit(vector<Minimizer *> &minimizer,
     return data_->fit(minimizer, init, vecPt);
 }
 
+// internal function to refresh fit ranges /////////////////////////////////////
 void CorrelatorFitter::refreshRanges(void)
 {
     for (unsigned int i = 0; i < range_.size(); ++i)
diff --git a/lib/Physics/CorrelatorFitter.hpp b/lib/Physics/CorrelatorFitter.hpp
index 018cb87..9acadb7 100644
--- a/lib/Physics/CorrelatorFitter.hpp
+++ b/lib/Physics/CorrelatorFitter.hpp
@@ -26,6 +26,9 @@
 
 BEGIN_LATAN_NAMESPACE
 
+/******************************************************************************
+ *                         Correlator types & models                          *
+ ******************************************************************************/
 enum class CorrelatorType {undefined, exp, cosh, sinh, linear, cst};
 
 namespace CorrelatorModels
@@ -46,12 +49,18 @@ namespace CorrelatorModels
     DVec        parameterGuess(const DMatSample &corr, const ModelPar par);
 };
 
+/******************************************************************************
+ *                       Correlator fit utility class                         *
+ ******************************************************************************/
 class CorrelatorFitter
 {
 public:
+    // constructors
     CorrelatorFitter(const DMatSample &corr);
     CorrelatorFitter(const std::vector<DMatSample> &corr);
+    // destructor
     virtual ~CorrelatorFitter(void) = default;
+    // access
     XYSampleData & data(void);
     void setCorrelator(const DMatSample &corr);
     void setCorrelators(const std::vector<DMatSample> &corr);
@@ -62,11 +71,13 @@ public:
     void setFitRange(const Index tMin, const Index tMax, const Index i = 0);
     void setCorrelation(const bool isCorrelated, const Index i = 0, 
                         const Index j = 0);
-    DMat getVarianceMatrix(void);
+    DMat getVarianceMatrix(void) const;
     void setThinning(const Index thinning, const Index i = 0);
+    // fit functions
     SampleFitResult fit(Minimizer &minimizer, const DVec &init);
     SampleFitResult fit(std::vector<Minimizer *> &minimizer, const DVec &init);
 private:
+    // internal function to refresh fit ranges
     void refreshRanges(void);
 private:
     Index                                nt_{0};
diff --git a/lib/Physics/EffectiveMass.cpp b/lib/Physics/EffectiveMass.cpp
index aa21126..7899843 100644
--- a/lib/Physics/EffectiveMass.cpp
+++ b/lib/Physics/EffectiveMass.cpp
@@ -23,6 +23,9 @@
 using namespace std;
 using namespace Latan;
 
+/******************************************************************************
+ *                       EffectiveMass implementation                         *
+ ******************************************************************************/
 // constructors ////////////////////////////////////////////////////////////////
 EffectiveMass::EffectiveMass(const CorrelatorType type)
 {