Hui Zhang 0002 Ashish Goel Ramesh Govindan Kahn Mason Benjamin Van Roy Making Eigenvector-Based Reputation Systems Robust to Collusion. 92-104 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3243&spage=92 2004 conf/waw/2004 WAW db/conf/waw/waw2004.html#ZhangGGMR04