Sandip Sen Partha Sarathi Dutta Sabyasachi Saha Emergence and Stability of Collaborations Among Rational Agents. 192-205 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2782&spage=192 2003 conf/cia/2003 CIA db/conf/cia/cia2003.html#SenDS03