Paolo Busetta Luciano Serafini Dhirendra Singh Floriano Zini Extending Multi-agent Cooperation by Overhearing. 40-52 2001 conf/coopis/2001 CoopIS http://link.springer.de/link/service/series/0558/bibs/2172/21720040.htm db/conf/coopis/coopis2001.html#BusettaSSZ01