Philip H. P. Nguyen Ken Kaneiwa Dan Corbett Minh-Quang Nguyen An Ontology Formalization of Relation Type Hierarchy in Conceptual Structure Theory. 79-85 2008 Australasian Conference on Artificial Intelligence http://dx.doi.org/10.1007/978-3-540-89378-3_8 conf/ausai/2008 db/conf/ausai/ausai2008.html#NguyenKCN08