1. An introduction to inductive definitions;Aczel,1977
2. Contributions to the theory of logic programming;Apt;Journal of the ACM,1982
3. Dualities between alternative semantics for logic programming and nonmonotonic reasoning;Baral,1991
4. Negation as failure;Clark,1978
5. The well-founded semantics is the principle of inductive definition;Denecker,1998