Index: cdt_test.c
===================================================================
--- cdt_test.c	(revision 33932)
+++ cdt_test.c	(revision 33933)
@@ -1,3 +1,30 @@
+/*
+    libcdtr - Constrained Delaunay Triangulation using incremental algorithm
+
+    Copyright (C) 2018, 2021 Wojciech Krutnik
+    Copyright (C) 2021 Tibor 'Igor2' Palinkas
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 2.1 of the License, or (at your option) any later version.
+
+    This library 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
+    Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+
+    Constrained Delaunay Triangulation using incremental algorithm, as described in:
+      Yizhi Lu and Wayne Wei-Ming Dai, "A numerical stable algorithm for constructing
+      constrained Delaunay triangulation and application to multichip module layout,"
+      China., 1991 International Conference on Circuits and Systems, Shenzhen, 1991,
+      pp. 644-647 vol.2.
+ */
+
 #include <stdio.h>
 #include <ctype.h>
 #include <time.h>