1. Batini, C., Ceri, S., Navathe, S.B.: Conceptual Database Design. In: An Entity-relationship Approach, p. 470. The Benjamin/Cummings Publishing Co. (1992)
2. Bouzeghoub, M., Kekad, Z., Métais, E.: CASE Tools: Computer Support for Conceptual Modeling. In: Piattini, M., Díaz, O. (eds.) Advanced Database Technology and Design, Artech House (2000)
3. Calvanese, D., Lenzerini, M., Nardi, D.: Description Logics for Conceptual Data Modeling. In: Chomicki, J., Saake, G. (eds.) Logics for Databases and IS, pp. 229–263. Kluwer, Dordrecht (1998)
4. Lecture Notes in Computer Science;S. Castano,1992
5. Conesa, J., de Palol, X.: A Case Study on Building Conceptual Schemas by Refining General Ontologies. In: UPC (2003), http://www.lsi.upc.es/~jconesa/casestudy.html