diff --git a/library/GSUP_Types.ttcn b/library/GSUP_Types.ttcn
index b994d1f..fc524a1 100644
--- a/library/GSUP_Types.ttcn
+++ b/library/GSUP_Types.ttcn
@@ -1,5 +1,17 @@
 module GSUP_Types {
 
+/* GSUP_Types, defining abstract TTCN-3 data types for the GSUP protocol.
+ *
+ * GSUP is a non-standard protocol used between OsmoMSC/OsmoSGSN and OsmoHLR
+ * in order to replace the complex TCAP/MAP protocol.
+ *
+ * (C) 2017 by Harald Welte <laforge@gnumonks.org>
+ * All rights reserved.
+ *
+ * Released under the terms of GNU General Public License, Version 2 or
+ * (at your option) any later version.
+ */
+
 import from General_Types all;
 import from Osmocom_Types all;