http://en.wikipedia.org/wiki/Massively_multiplayer_online_game
http://www.xbox.com/en-US/community/personality/ryan/20060130-mmogames.htm
http://www.tentonhammer.com/index.php?module=ContentExpress&file=index&func=display&ceid=34&meid=42
http://hardcodedgames.com/mmpgamedev/2005/08/study-mmo-games-cause-violence-not.html
http://www.mmoz.com/forum/forumdisplay.php?f=1
http://blogs.ign.com/Indices/Blogs/mmo_games/5044/
http://www.tentonhammer.com/index.php?module=ContentExpress&file=index&func=display&ceid=34&meid=42
http://www.meiobit.com/arq/007939.html