1. Narrowing as an Incremental Constraint Satisfaction Algorithm;Alpuente,1991
2. The Semantics of Equational Logic Programming as an Instance of CLP;Alpuente,1993
3. Introduction to Logic Programming;Apt,1990
4. Towards a Theory of Declarative Knowledge;Apt,1988
5. Apt, K.R., and Gabbrielli, M., Declarative Interpretations Reconsidered,Report, CWI, Amsterdam.