R. Duque, C. Bravo, und M. Ortega. Proceedings of the 15th International Conference on Conceptual Structures (ICCS 2007), Volume 4604 von Lecture Notes in Artificial Intelligence, Seite 509-512. Berlin, Heidelberg, Springer-Verlag, (Juli 2007)
G. Torres, A. Lorenzatti, V. Rey, R. Rocha, und M. Abel. Proceedings of Joint IV Seminar on Ontology Research in Brazil and VI International Workshop on Metamodels, Ontologies and Semantic Technologies, 776, Seite 201-206. Gramado, Brazil, CEURS-WS, (2011)