diff --git a/src/Examples/TimerExample.cpp b/src/Examples/TimerExample.cpp
index 49bafb25c5b4cdd413051b815905bea340401eb6..aa40367341170b319db7198c8db69873137d8aae 100644
--- a/src/Examples/TimerExample.cpp
+++ b/src/Examples/TimerExample.cpp
@@ -16,5 +16,7 @@ int main()
     time.reset();
     cout << "after reset:" << time.getRealTime() << endl;
     // writeLog example
+    Logger log1(50,stream);
+    writeLog( log1, 0 );
 }
 
diff --git a/src/TNL/Assert.h b/src/TNL/Assert.h
index dabd69a9738ef651a1484ead245a41b956ce1663..d601f9c1b95dd7e85737304c05a3536ac0d0f8ae 100644
--- a/src/TNL/Assert.h
+++ b/src/TNL/Assert.h
@@ -103,6 +103,7 @@
  * The assertion succeeds if, and only if, ___tnl__assert_condition is valid.
  * On success the test continues without any side effects.
  * On failure the test is terminated with the error message \e ___tnl__assert_command.
+ */
 #define TNL_ASSERT( ___tnl__assert_condition, ___tnl__assert_command )
 
 #else /* #ifdef NDEBUG */
diff --git a/src/TNL/Config/ConfigDescription.h b/src/TNL/Config/ConfigDescription.h
index d193869580bae369c5698936fa92943f3d37fa65..833e99a47af2a11b19fcdbd3b2ed9c5f5cccf0f4 100644
--- a/src/TNL/Config/ConfigDescription.h
+++ b/src/TNL/Config/ConfigDescription.h
@@ -48,7 +48,7 @@ class ConfigDescription
    }
 
    /**
-    * \brief Adds new entry to the configuration description.
+    * \brief Adds new entry to the configuration description, that requires set value.
     *
     * \tparam EntryType Type of the entry.
     * \param name Name of the entry.
@@ -98,7 +98,7 @@ class ConfigDescription
    }
 
    /**
-    * \brief Adds new list to the configuration description.
+    * \brief Adds new list to the configuration description, that requires specific value.
     *
     * \tparam EntryType Type of the list.
     * \param name Name of the list.
@@ -132,6 +132,13 @@ class ConfigDescription
       entries. Append( currentEntry );
    }
 
+   /**
+    * \brief Adds new entry enumeration of type \e EntryType.
+    *
+    * Adds new option of setting an entry value.
+    * \tparam EntryType Type of the entry enumeration.
+    * \param entryEnum Value of the entry enumeration.
+    */
    template< typename EntryType >
    void addEntryEnum( const EntryType& entryEnum )
    {
@@ -139,18 +146,34 @@ class ConfigDescription
       ( ( ConfigEntry< EntryType >* ) currentEntry )->getEnumValues().Append( entryEnum );
    }
 
+   /**
+    * \brief Adds new entry enumeration of type \e char.
+    *
+    * Adds new option of setting an entry value.
+    * \param entryEnum Value of the entry enumeration.
+    */
    void addEntryEnum( const char* entryEnum )
    {
       TNL_ASSERT( this->currentEntry,);
       ( ( ConfigEntry< String >* ) currentEntry )->getEnumValues().Append( String( entryEnum ) );
    }
 
+   /**
+    * \brief Adds delimeter/section to the configuration description.
+    *
+    * \param delimeter String that defines how the delimeter looks like.
+    */
    void addDelimiter( const String& delimiter )
    {
       entries.Append( new ConfigDelimiter( delimiter ) );
       currentEntry = 0;
    }
 
+   /**
+    * \brief Gets entry out of the configuration description.
+    *
+    * \param name Name of the entry.
+    */
    const ConfigEntryBase* getEntry( const String& name ) const
    {
       for( int i = 0; i < entries.getSize(); i++ )
@@ -195,7 +218,13 @@ class ConfigDescription
       return NULL;
    }
 
-   //! If there is missing entry with defined default value in the Config::ParameterContainer it is going to be added
+   /**
+    * \brief Fills in the parameters from the \e parameter_container.
+    *
+    * Parameters which were not defined in the command line by user but have their default value are added to the congiguration description.
+    * If there is missing entry with defined default value in the Config::ParameterContainer it is going to be added.
+    * \param parameter_container Name of the ParameterContainer object.
+    */
    void addMissingEntries( Config::ParameterContainer& parameter_container ) const;
 
    //! Check for all entries with the flag 'required'.
@@ -205,6 +234,11 @@ class ConfigDescription
                              bool printUsage,
                              const char* programName ) const;
 
+   /**
+    * \brief Prints configuration description with the \e program_name at the top.
+    *
+    * \param program_name Name of the program
+    */
    void printUsage( const char* program_name ) const;
 
    //bool parseConfigDescription( const char* file_name );
diff --git a/src/TNL/Timer.h b/src/TNL/Timer.h
index bcbeaca28d0cbf061867f07bf0df454fa3842b0d..a2e01ea8eea32d53a072fbf9ab866a6ca4f499ab 100644
--- a/src/TNL/Timer.h
+++ b/src/TNL/Timer.h
@@ -85,7 +85,7 @@ class Timer
 
       /// \brief Writes a record into the \e logger.
       ///
-      /// \param logger
+      /// \param logger Name of Logger object.
       /// \param logLevel A non-negative integer recording the log record indent.
       bool writeLog( Logger& logger, int logLevel = 0 ) const;