License

1. Stockfish is a free, powerful UCI chess engine derived from Glaurung 2.1. It is licesnsed by GNU General Public License version 3 (GPL v3). Source code can be found at Github.
2. "Chess Fundamentals", by José Raúl Capablanca, originally published in 1921. Capablanca (19 November 1888 – 8 March 1942) was a Cuban chess player who was world chess champion from 1921 to 1927. One of the greatest players of all time, he was renowned for his exceptional endgame skill and speed of play. Due to his achievements in the chess world, mastery over the board and his relatively simple style of play he was nicknamed the "Human Chess Machineli.
3. "Modern Ideas in Chess", by Richard Réti, originally published in 1923, is one of the rare books that transcends the time frame in which it was written. It stands on its own, timeless, one of the true classics in the literature of the game. Richard Réti (28 May 1889 – 6 June 1929) was an Austro-Hungarian, later Czechoslovak chess grandmaster, chess author, and composer of endgame studies. He was one of the principal proponents of hypermodernism in chess.
4. Stratkat and Epic Battle Fantasy III musics from The Open Game Art Bundle, is licensed by Creative Commons Zero License
5. Unique images and icons are licensed from Chang Design Lab.
6. Some icons made by Flat Icons, Freepik, geotatah, monkik, Pixel perfect and smalllikeart from www.flaticon.com are licensed by Creative Commons BY 3.0.