Jean Bézivin Richard Lemesle Ontology-Based Layered Semantics for Precise OA&D Modeling. 151-154 1997 conf/ecoopw/1997 ECOOP Workshops http://link.springer.de/link/service/series/0558/bibs/1357/13570151.htm db/conf/ecoopw/ecoopw97.html#BezivinL97