diff --git a/library/GSMTAP_PortType.ttcn b/library/GSMTAP_PortType.ttcn
index a3f655d..47796c8 100644
--- a/library/GSMTAP_PortType.ttcn
+++ b/library/GSMTAP_PortType.ttcn
@@ -1,4 +1,13 @@
-/* dual-faced port that wraps an IPL4asp port and encodes/decodes GSMTAP */
+/* dual-faced port that wraps an IPL4asp port and encodes/decodes GSMTAP
+ * (C) 2017 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.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
 module GSMTAP_PortType {
 	import from GSMTAP_Types all;
 	import from IPL4asp_PortType all;