Silvia Rossi Paolo Busetta Towards Monitoring of Group Interactions and Social Roles via Overhearing. 47-61 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3191&spage=47 2004 conf/cia/2004 CIA db/conf/cia/cia2004.html#RossiB04