diff --git a/include/rosa/support/csv/CSVWriter.hpp b/include/rosa/support/csv/CSVWriter.hpp
index 8fc2eed..a077e3d 100755
--- a/include/rosa/support/csv/CSVWriter.hpp
+++ b/include/rosa/support/csv/CSVWriter.hpp
@@ -1,218 +1,221 @@
 //===-- rosa/support/csv/CSVWriter.hpp --------------------------*- C++ -*-===//
 //
 //                                 The RoSA Framework
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file rosa/support/csv/CSVWriter.hpp
 ///
 /// \authors David Juhasz    (david.juhasz@tuwien.ac.at)
 ///          Edwin Willegger (edwin.willegger@tuwien.ac.at)
 ///
 /// \date 2017-2019
 ///
 /// \brief Facitilities to write CSV files.
 ///
 //===----------------------------------------------------------------------===//
 
 #ifndef ROSA_SUPPORT_CSV_CSVWRITER_HPP
 #define ROSA_SUPPORT_CSV_CSVWRITER_HPP
 
 #include <iostream>
 #include <ostream>
 
 #include <tuple>
 #include <vector>
 #include <array>
 
 #include "rosa/support/log.h"
 
 namespace rosa {
 namespace csv {
 
 /// Provides facilities to write values into a CSV file.
 ///
 /// The writer emits a comma, the character `,`, between each written values.
 /// The resulted stream is a flat CSV file as it consists of onlyone row, no new
 /// line is emitted.
 ///
 /// \tparam T type of values to write
 template <typename T>
 class CSVWriter {
 public:
   /// Creates a new instance.
   ///
   /// \param [in,out] S output stream to write to
   ///
   /// \note The writer operates on non-binary outputs as long as \p S is in
   /// good state.
   CSVWriter(std::ostream &S)
       : Str(S.good() && !(S.flags() & std::ios::binary) ? &S : nullptr),
         IsFirst(true) {}
 
   /// Tells if the last operation was successful.
   ///
   /// \return if the last operation was successful
   bool good(void) const noexcept {
     return Str != nullptr;
   }
 
   /// Writes an entry to the output stream.
   ///
   /// The implementation does anything only if the last operation was
   /// successful. If so, \p V is written to \c rosa::csv::CSVWriter::Str.
   /// The emitted value is preceded with a comma if the actual call is not the
   /// first one for \p this object. Success of the operation is checked at the
   /// end.
   ///
   /// \param V value to write
   void write(const T &V) {
     if (Str) {
       if (!IsFirst) {
         *Str << ',';
       } else {
         IsFirst = false;
       }
       *Str << V;
       if (!Str->good()) {
         Str = nullptr;
       }
     }
   }
 
 private:
   std::ostream *Str; ///< Output stream to write to.
   bool IsFirst;      ///< Denotes if the next write would be the first one.
 };
 
 /// Writes a tuple of values into a CSV file
 ///
 /// \tparam Ts types of values to write
 template <typename... Ts> class CSVTupleWriter {
 
 public:
 
 //    typedef <Ts...> value_type ;  ///< Type of values written.
     typedef std::tuple<Ts...> value_type;
 
     /// Creates a new instance.
     ///
     /// \param [in,out] S output stream to write to
     ///
     /// \note The writer operates on non-binary outputs as long as \p S is in
     /// good state.
     CSVTupleWriter(std::ostream &S)
         : Str(S.good() && !(S.flags() & std::ios::binary) ? &S : nullptr), 
           IsHeaderWritten(false), IsDataWritten(false) {}
 
     /// Tells if the last operation was successful.
     ///
     /// \return if the last operation was successful
     bool good(void) const noexcept {
       return Str != nullptr;
     }
 
 
     /// Write the values of a tuple to a CSV file with \c rosa::csv::CSVTupleWriter.
     ///
     /// \see rosa::csv::CSVTupleWriter
     ///
     /// 
     /// \param [in,out] values tuple, which values are written in a recusive fashion into a stream.
     template<size_t i = 0>
     void write(const std::tuple<Ts...> &values) {
         constexpr size_t size = sizeof...(Ts);
 
         LOG_TRACE_STREAM << "Writing tuple values into file \n"; 
         LOG_TRACE_STREAM << " Tuple has " << std::to_string(size) << " elements. \n";
 
         LOG_TRACE_STREAM << " Value is " << std::get<i>(values);
 
         if(Str){
             /// Write the current element of the tuple into the stream and add a separtor after it, 
             /// and call the function for the next element in the tuple.
             if constexpr(i+1 != sizeof...(Ts)){
                 *Str << std::get<i>(values) << ", ";
                 write<i+1>(values);
             /// If the last element is written into the stream than begin a new line. 
             }else if constexpr(i + 1 == sizeof...(Ts)){
                 *Str << std::get<i>(values) << '\n';
                 /// every time the last data value of a line is written, the flag indicates that data was already written into the file.
                 IsDataWritten = true; 
             }
         }
     }
 
-
     /// Write the header values to a CSV file with \c rosa::csv::CSVTupleWriter.
     ///
+    /// \note The function has no effect if anything has already been written
+    /// to the output stream either by \c
+    /// rosa::csv::CSVTupleWriter::writeHeader() or \c
+    /// rosa::csv::CSVTupleWriter::write().
+    ///
     /// \see rosa::csv::CSVTupleWriter
     ///
-    /// \param header the content of the header line. 
-    /// 
+    /// \param header the content of the header line.
     void writeHeader(const std::array<std::string, sizeof...(Ts)> &header){
         size_t index = 0;
         /// write into the stream only, if it is not a nullptr, and if no data and no header was already written into it. 
         if(Str && IsDataWritten == false && IsHeaderWritten == false){
             index = 0;
             for (auto i = header.begin(); i != header.end(); ++i){
                 index = index + 1;
                 /// write into the stream every entry with a delimeter, in this case ", " until 
                 /// the last entry
                 if(index != header.size()){
                     *Str << *i << ", ";
                 /// write the last entry into the stream, without any delimeter
                 }else {
                     *Str << *i;
                 }
             }
             /// finish the header line and start a new line.
             *Str << '\n';
             /// now it is not possible to write additional header lines. 
             IsHeaderWritten = true;
         }
     }
 
 private:
     std::ostream *Str;              ///< Output stream to write to.
     bool          IsHeaderWritten;  ///< If an header line was already written into the stream. If set than no additional header could be written.
     bool          IsDataWritten;    ///< If one line of data has already been written into the stream, than no headerline could be added. 
 };
 
 /// Writes all values of a tuple to a CSV file with \c rosa::csv::CSVTupleWriter.
 ///
 /// \see rosa::csv::CSVTupleWriter
 ///
 /// \tparam Ts types of values to write
 ///
 /// \param [in,out] W object to write with
 /// \param V values to write
 ///
 /// \return \p W after writing \p V with it
 template <typename... Ts>
 CSVTupleWriter<Ts...> &operator<<(CSVTupleWriter<Ts...> &W, const std::tuple<Ts...> &V)
 {
     W.write(V);
     return W;
 }
 
 /// Writes a value to a CSV file with \c rosa::csv::CSVWriter.
 ///
 /// \see rosa::csv::CSVWriter
 ///
 /// \tparam T type of value to write
 ///
 /// \param [in,out] W object to write with
 /// \param V value to write
 ///
 /// \return \p W after writing \p V with it
 template <typename T>
 CSVWriter<T> &operator<<(CSVWriter<T> &W, const T& V) {
   W.write(V);
   return W;
 }
 
 } // End namespace csv
 } // End namespace rosa
 
 #endif // ROSA_SUPPORT_CSV_CSVWRITER_HPP