Franco Arcieri Fabio Fioravanti Roberto Giaccio Enrico Nardelli Maurizio Talamo Certifying performance of cooperative services in a digital government framework. 249-256 2003 conf/saint/2003 SAINT http://computer.org/proceedings/saint/1872/18720249abs.htm db/conf/saint/saint2003.html#ArcieriFGNT03