1. Ait-Kaci, H. and R. Nasr (1985) LOGIN: A Logic Programming Language with Built-in Inheritance, MCC Technical Report number AI-068-85.
2. Attardi, G. and M. Simi (1981a) Consistency and Completeness of Omega, a Logic for Knowledge Representation. IJCAI. Vancouver.
3. Attardi, G. and M. Simi (1981b) Semantics of Inheritance and Attributions in the Description System Omega. AI Memo 642, M.I.T.
4. Attardi, G. and M. Simi (1984) Metalanguage and Reasoning across Viewpoints. Proc. of Sixth European Conference on Artificial Intelligence, Pisa.
5. Attardi, G., A. Corradini, S. Diomedi and M. Simi (1986) Taxonomic Reasoning, Proc. of ECAI 86, Brighton.