Stijn Heymans Davy Van Nieuwenborgh Dirk Vermeir Nonmonotonic Ontological and Rule-Based Reasoning with Extended Conceptual Logic Programs. 392-407 2005 conf/esws/2005 ESWC http://dx.doi.org/10.1007/11431053_27 db/conf/esws/eswc2005.html#HeymansNV05