docs: Updating copyright notices in files
diff --git a/docs/doxygen.hpp b/docs/doxygen.hpp
index 008ebdb..e2d9815 100644
--- a/docs/doxygen.hpp
+++ b/docs/doxygen.hpp
@@ -1,3 +1,22 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2011-2015 Regents of the University of California.
+ *
+ * This file is part of ndnSIM. See AUTHORS for complete list of ndnSIM authors and
+ * contributors.
+ *
+ * ndnSIM 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.
+ *
+ * ndnSIM 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
+ * ndnSIM, e.g., in COPYING.md file. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
/**
* \mainpage ndnSIM documentation
*