diff --git a/source/common/engine/i_net.cpp b/source/common/engine/i_net.cpp
index 0563c40b1..c7c5881b4 100644
--- a/source/common/engine/i_net.cpp
+++ b/source/common/engine/i_net.cpp
@@ -5,6 +5,23 @@
 //
 // Copyright (C) 1993-1996 by id Software, Inc.
 //
+// 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/
+//
+//
+//
+// Alternatively the following applies:
+//
 // This source is available for distribution and/or modification
 // only under the terms of the DOOM Source Code License as
 // published by id Software. All rights reserved.
@@ -14,6 +31,7 @@
 // FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
 // for more details.
 //
+//
 // DESCRIPTION:
 //		Low-level networking code. Uses BSD sockets for UDP networking.
 //
diff --git a/source/core/d_net.cpp b/source/core/d_net.cpp
index 4a4737743..d719a479c 100644
--- a/source/core/d_net.cpp
+++ b/source/core/d_net.cpp
@@ -7,6 +7,23 @@
 // Copyright 1999-2016 Randy Heit
 // Copyright 2002-2020 Christoph Oelckers
 //
+// 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/
+//
+//
+//
+// Alternatively the following applies:
+//
 // This source is available for distribution and/or modification
 // only under the terms of the DOOM Source Code License as
 // published by id Software. All rights reserved.
diff --git a/source/core/mainloop.cpp b/source/core/mainloop.cpp
index c26297a2d..10a4606e4 100644
--- a/source/core/mainloop.cpp
+++ b/source/core/mainloop.cpp
@@ -33,7 +33,8 @@
 */
 
 
-// For G_Ticker and TryRunTics the following applies:
+// For TryRunTics the following applies:
+// For TryRunTics the following applies:
 //-----------------------------------------------------------------------------
 //
 // $Id:$