David D. McDonald Alice Leung William Ferguson Talib S. Hussain An Abstraction Framework for Cooperation Among Agents and People in a Virtual World. 54-59 2006 conf/aiide/2006 AIIDE db/conf/aiide/aiide2006.html#McDonaldLFH06 http://www.aaai.org/Library/AIIDE/2006/aiide06-013.php