diff --git a/doc/Doxyfile.in b/doc/Doxyfile.in
index d8dc49a45866cc1b115ccfacde6a8069695be1f2..f6eb5f4e448d19eaf1c0bd79c3dc99c911a6eb6d 100644
--- a/doc/Doxyfile.in
+++ b/doc/Doxyfile.in
@@ -668,7 +668,7 @@ WARN_LOGFILE           =
 # directories like "/usr/src/myproject". Separate the files or directories
 # with spaces.
 
-INPUT                  = @top_srcdir@/src
+INPUT                  = @top_srcdir@/include @top_srcdir@/src
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding, which is
diff --git a/include/calendar.h b/include/calendar.h
index 9dc301b41c1fd26f85153c69143b4a0c58e8d85a..b53fbe88ed3806bd34eeada912513cedcb3d3a31 100644
--- a/include/calendar.h
+++ b/include/calendar.h
@@ -1,13 +1,29 @@
+/**
+ * @addtogroup CBindings libmtime C language bindings
+ *
+ * @file calendar.c
+ * 
+ * @brief Singleton Calendar connecting all supported calendar types.
+ *
+ * @author Luis Kornblueh, Rahul Sinha. MPIM.
+ * @date March 2013
+ *
+ * @note Calendar type, once initialized, should not be changed.
+ */
 #ifndef CALENDAR_H
 #define CALENDAR_H
 
-#include <stdlib.h>
-
 #define MAX_CALENDAR_STR_LEN 32
 
 struct _datetime;
 struct _julianday;
 
+/**
+ * @enum  calendarType
+ * 
+ * @brief calendar selector 
+ */
+
 typedef enum
 {
   CALENDAR_NOT_SET = 0, PROLEPTIC_GREGORIAN = 1, YEAR_OF_365_DAYS = 2, YEAR_OF_360_DAYS = 3
diff --git a/src/calendar.c b/src/calendar.c
index 01455c95b3441ca64ac26ef2de1d6367bb41f4d9..9aa132e427dc044b5dcbb40493bc187acbc5f904 100644
--- a/src/calendar.c
+++ b/src/calendar.c
@@ -1,4 +1,6 @@
 /**
+ * @addtogroup CBindings libmtime C language bindings
+ *
  * @file calendar.c
  * 
  * @brief Singleton Calendar connecting all supported calendar types.
@@ -10,6 +12,7 @@
  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <stdbool.h>
 
@@ -29,7 +32,6 @@ struct _datetime *
 (*julian2date)(struct _julianday *julian, struct _datetime *date);
 /*! \endcond */
 
-
 static calendarType _calendar_type = CALENDAR_NOT_SET;
 
 static bool calendar_initialized = false;
diff --git a/src/date.c b/src/date.c
index 5e8242d838ba16cf30d7ad43da2cae24be34aa07..fe81a63681eb5bb75afd9ed2ae403ef8d599525b 100644
--- a/src/date.c
+++ b/src/date.c
@@ -1,4 +1,6 @@
 /**
+ * \addtogroup CBindings libmtime C language bindings
+ * 
  * @file date.c
  * 
  * @brief Date and some operations supported on Date.
diff --git a/src/libmtime.f90 b/src/libmtime.f90
index 416a61a5016948c7bb9430b699d0c61ee24417d5..24e6214312c550c4685b6b8e993e1e766d7d2d67 100644
--- a/src/libmtime.f90
+++ b/src/libmtime.f90
@@ -5,8 +5,8 @@
 !! @author  Luis Kornblueh, Max Planck Institute for Meteorology
 !! @author  Rahul Sinha, Max Planck Institute for Meteorology
 !!
-!! defgroup FortranBindings libmtime Fortran language bindings
-!!___________________________________________________________________________________________________________
+!! @defgroup FortranBindings libmtime Fortran language bindings
+!___________________________________________________________________________________________________________
 !>
 !! @brief Provides the calendar to the users, abstracting the different calendars available.
 !!
@@ -23,7 +23,7 @@
 !!
 !! @author  Luis Kornblueh, Max Planck Institute for Meteorology
 !! @author  Rahul Sinha, Max Planck Institute for Meteorology
-!!___________________________________________________________________________________________________________
+!___________________________________________________________________________________________________________
 module mtime_calendar
   !
   use, intrinsic :: iso_c_binding, only: c_int, c_char, c_null_char
@@ -32,6 +32,7 @@ module mtime_calendar
   !
   private
   !
+   
   enum, bind(c)
     enumerator :: calendar_not_set    = 0   !> calendar is not defined yet
     enumerator :: proleptic_gregorian = 1   !> proleptic Gregorian calendar
@@ -85,7 +86,7 @@ contains
 end module mtime_calendar
 !>
 !!
-!!___________________________________________________________________________________________________________
+!___________________________________________________________________________________________________________
 module mtime_julianday
   !
   use, intrinsic :: iso_c_binding, only: c_int64_t, c_char, c_null_char, c_ptr, c_loc, c_f_pointer
@@ -161,7 +162,7 @@ contains
 end module mtime_julianday
 !>
 !!
-!!___________________________________________________________________________________________________________
+!___________________________________________________________________________________________________________
 module mtime_date
   !
   use, intrinsic :: iso_c_binding, only: c_int, c_int64_t, c_char, c_ptr, c_null_char, c_loc, c_f_pointer
@@ -238,7 +239,7 @@ contains
 end module mtime_date
 !>
 !!
-!!___________________________________________________________________________________________________________
+!___________________________________________________________________________________________________________
 module mtime_time
   !
   use, intrinsic :: iso_c_binding, only: c_int, c_char, c_ptr, c_null_char, c_loc, c_f_pointer
@@ -315,7 +316,7 @@ contains
 end module mtime_time
 !>
 !!
-!!___________________________________________________________________________________________________________
+!___________________________________________________________________________________________________________
 module mtime_datetime
   !
   use, intrinsic :: iso_c_binding, only: c_int, c_int64_t, c_char, c_ptr, c_null_char, c_loc, c_f_pointer
@@ -603,7 +604,7 @@ contains
 end module mtime_datetime
 !>
 !!
-!!___________________________________________________________________________________________________________
+!___________________________________________________________________________________________________________
 module mtime_timedelta
   !
   use, intrinsic :: iso_c_binding, only: c_int, c_int64_t, c_char, c_ptr, c_null_char, c_loc, c_f_pointer
@@ -717,7 +718,7 @@ contains
 end module mtime_timedelta
 !>
 !!
-!!___________________________________________________________________________________________________________
+!___________________________________________________________________________________________________________
 module mtime_events
   !
   use, intrinsic :: iso_c_binding, only: c_int64_t, c_char, c_null_char, c_bool, c_ptr, c_loc, c_f_pointer
@@ -818,7 +819,7 @@ contains
 end module mtime_events
 !>
 !!
-!!___________________________________________________________________________________________________________
+!___________________________________________________________________________________________________________
 module mtime_eventgroups
   !
   use, intrinsic :: iso_c_binding, only: c_int64_t, c_ptr, c_char, c_null_char, c_bool, c_loc, c_f_pointer
@@ -906,7 +907,7 @@ contains
 end module mtime_eventgroups
 !>
 !!
-!!___________________________________________________________________________________________________________
+!___________________________________________________________________________________________________________
 module mtime
   !
   use, intrinsic :: iso_c_binding, only: c_int, c_int64_t, c_bool, c_ptr, c_char
diff --git a/src/time.c b/src/time.c
index 196e89adb59b3afc12f90f256b126e4c080eb45d..519333899e6c05e52c4d645516a32a9584bde357 100644
--- a/src/time.c
+++ b/src/time.c
@@ -1,4 +1,6 @@
 /**
+ * @addtogroup CBindings libmtime C language bindings
+ *
  * @file time.c
  * 
  * @brief Time and some operations supported on Time.