1. Acyclic Programs;Apt,1990
2. Acyclic Programs;Apt;New Generation Computing,1991
3. Logic Programming and Negation: A Survey;Apt;Journal of Logic Programming,1994
4. A New Definition of SLDNF Resolution;Apt;Journal of Logic Programming,1994
5. SLX—A Top-Down Derivation Procedure for Programs with Explicit Negation;Alferes,1994