Hai Jin Zuoning Yin Xudong Yang Fucheng Wang Jie Ma Hao Wang Jiangpei Yin APPLE: A Novel P2P Based e-Learning Environment. 52-62 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3326&spage=52 2004 conf/iwdc/2004 IWDC db/conf/iwdc/iwdc2004.html#JinYYWMWY04