No, that's pretty much it. From the GPLv3 text, add this to your program:
Copyright (C)
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 .
The "contract" is this: without the GPL, no one but you has any right to distribute your program. They have no copying rights. The GPL says that if they abide by its terms, then you grant them the additional rights of distributing copies of your code.
There are other Free/Open Source Software licenses, but I'm just using this as an example.
