1. C. Baral, J. Lobo, and J. Minker. Generalized disjunctive well-founded semantics for logic programs: Declarative semantics. Submitted to ICLP 90.
2. J. Chomicki and V. S. Subrahmanian. Generalized closed world assumption is π0 2 complete. Technical Report TR 89-036, Department of Computer Science, University of North Carolina at Chapel Hill, October 1989.
3. M. Gelfond and V. Lifschitz. The Stable Model Semantics for Logic Programming. In R.A. Kowalski and K.A. Bowen, editors, Proc. 5th International Conference and Symposium on Logic Programming, pages 1070–1080, Seattle, Washington, August 15–19 1988.
4. J.W. Lloyd. Foundations of Logic Programming. Springer-Verlag, 1984.
5. J. Minker. On Indefinite Databases and the Closed World Assumption. In Lecture Notes in Computer Science 138, pages 292–308. Springer-Verlag, 1982.