http://jonas.nitro.dk/bittorrent/bittorrent-rfc.html http://bittorrent.org/beps/bep_0003.html http://bittorrent.org/beps/bep_0005.html https://wiki.theory.org/BitTorrentSpecification http://wiki.vuze.com/w/Azureus_messaging_protocol Some random overview http://www.kristenwidman.com/blog/33/how-to-write-a-bittorrent-client-part-1/ http://www.kristenwidman.com/blog/71/how-to-write-a-bittorrent-client-part-2/