1. Fixpoint extensions of first-order logic and datalog-like languages;Abiteboul,1989
2. The muse or-parallel prolog model and its performance;Ali,1990
3. Towards a theory of declarative knowledge;Apt,1989
4. Logic programming and negation: a survey;Apt;Journal of Logic Programming,1994
5. Y. Babovich, CModels, , 2002.