Stefania Galizia Alessio Gugliotta Carlos Pedrinaci A Formal Model for Classifying Trusted Semantic Web Services. 540-554 2008 ASWC http://dx.doi.org/10.1007/978-3-540-89704-0_37 conf/aswc/2008 db/conf/aswc/aswc2008.html#GaliziaGP08