Nadira Lammari Cédric du Mouza Elisabeth Métais POEM: An Ontology Manager Based on Existence Constraints. 81-88 2008 DEXA http://dx.doi.org/10.1007/978-3-540-85654-2_10 conf/dexa/2008 db/conf/dexa/dexa2008.html#LammariMM08