--- a/Makefile	Tue Apr 05 14:24:07 2011 +0100
+++ b/Makefile	Tue Apr 05 17:12:12 2011 +0100
@@ -1,3 +1,21 @@
+# matiec - a compiler for the programming languages defined in IEC 61131-3
+#
+# Copyright (C) 2003-2011  Mario de Sousa (msousa@fe.up.pt)
+# Copyright (C) 2007-2011  Laurent Bessard and Edouard Tisserant
+#
+# This program 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 of the License, or
+# (at your option) any later version.
+#
+# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
 # include the system specific Makefile
 include Makefile.$(shell uname)