Alessandro Agostini Paolo Avesani Advertising Games for Web Services. 93-109 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2888&spage=93 2003 conf/coopis/2003 CoopIS/DOA/ODBASE db/conf/coopis/coopis2003.html#AgostiniA03