* The source code is released by its authors (credited in the game) under the GPL version 3 or any later version.
* The cover art is released by Victor Gijsbers in the public domain. The image was taken from Wikimedia, where it too is claimed to be in the public domain. (The painting is by Elias Gottlob Haussmann, 1746.)
* The music was written by Ludwig van Beethoven in 1825-1826. Copyright of this performance by Daniel Bautista, who has released it under the Creative Commons Attribution-ShareAlike 3.0 Unported license: http://creativecommons.org/licenses/by-sa/3.0/. He has given permission to include it in this game.