Valeria Cardellini Emiliano Casalicchio Vincenzo Grassi Francesco Lo Presti Flow-Based Service Selection forWeb Service Composition Supporting Multiple QoS Classes. 743-750 2007 conf/icws/2007 ICWS http://doi.ieeecomputersociety.org/10.1109/ICWS.2007.91 db/conf/icws/icws2007.html#CardelliniCGP07