1. Introduction to Logic Programming;Apt,1987
2. Handbook of Theoretical Computer Science, North-Holland, Amsterdam, to appear.
3. On the integration of logic programming and functional programming;Barbuti,1984
4. LEAF: A language which integrates logic, equations and functions;Barbuti,1986
5. The Lambda-Calculus: Its Syntax and Semantics;Barendregt,1984