1. Ben-Eliyahu, R., Dechter, R.: Propositional Semantics for Disjunctive Logic Programs. Annals of Mathematics and Artificial Intelligence 12, 53–87 (1994)
2. Bidoit, N., Froidevaux, C.: Negation by Default and Unstratifiable Logic Programs. Theoretical Computer Science 78, 85–112 (1991)
3. Brass, S., Dix, J.: Semantics of (Disjunctive) Logic Programs Based on Partial Evaluation. Journal of Logic Programming 38(3), 167–213 (1999)
4. Brignoli, G., Costantini, S., D’Antona, O., Provetti, A.: Characterizing and Computing Stable Models of Logic Programs: The Non-stratified Case. In: Proc. of the 2nd International Conference on Information Technology (CIT 1999), pp. 197–201 (1999)
5. Clark, K.L.: Negation as Failure. In Logic and Databases, pp. 293–322. Plenum, New York (1978)