Floriana Esposito Nicola Fanizzi Claudia d'Amato Conceptual Clustering Applied to Ontologies. 42-56 2007 MCD http://dx.doi.org/10.1007/978-3-540-68416-9_4 conf/ecml/2007mcd db/conf/ecml/mcd2007.html#EspositoFd07