diff --git a/lib/receiver/gsm_constants.h b/lib/receiver/gsm_constants.h
index 01d089b..131d923 100644
--- a/lib/receiver/gsm_constants.h
+++ b/lib/receiver/gsm_constants.h
@@ -1,3 +1,25 @@
+/* -*- c++ -*- */
+/*
+ * @file
+ * @author Piotr Krysik <ptrkrysik@gmail.com>
+ * @section LICENSE
+ *
+ * Gr-gsm is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ *
+ * Gr-gsm is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with gr-gsm; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+ 
 #ifndef INCLUDED_GSM_CONSTANTS_H
 #define INCLUDED_GSM_CONSTANTS_H