Tania Tudorache Natalya Fridman Noy Samson W. Tu Mark A. Musen Supporting Collaborative Ontology Development in Protégé. 17-32 2008 International Semantic Web Conference http://dx.doi.org/10.1007/978-3-540-88564-1_2 conf/semweb/2008 db/conf/semweb/iswc2008.html#TudoracheNTM08