Anna Perini Marco Pistore Marco Roveri Angelo Susi Agent-Oriented Modeling by Interleaving Formal and Informal Specification. 36-52 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2935&spage=36 2003 conf/aose/2003 AOSE db/conf/aose/aose2003.html#PeriniPRS03