Dominik Heckmann Eric Schwarzkopf Junichiro Mori Dietmar Dengler Alexander Kröner The User Model and Context Ontology GUMO Revisited for Future Web 2.0 Extensions. 2007 C&O:RR http://ceur-ws.org/Vol-298/paper4.pdf conf/context/2007corr db/conf/context/corr2007.html#HeckmannSMDK07