[ACM Press the 6th international joint conference - Honolulu, Hawaii (2007.05.14-2007.05.18)] Proceedings of the 6th international joint conference on Autonomous agents and multiagent systems - AAMAS '07 - An incentive mechanism for message relaying in unstructured peer-to-peer systemsLi, Cuihong; Yu, Bin; Sycara, Katia · 2007