Vassilis Christophides Gregory Karvounarakis Ioanna Koffina Giorgos Kokkinidis Aimilia Magkanaraki Dimitris Plexousakis Giorgos Serfiotis Val Tannen The ICS-FORTH SWIM: A Powerful Semantic Web Integration Middleware. 381-393 2003 conf/semweb/2003swdb SWDB db/conf/semweb/swdb2003.html#ChristophidesKKKMPST03