1. H. Gallaire and J. Minker,Logic and Data Bases, Plenum Press, New York, 1978.
2. L. Kerschberg,Expert Database Systems, The Benjamin/Cummings Publishing Company, Menlo Park, CA, 1987.
3. D.J. Israel, ?The role of logic in knowledge representation,?Computer, pp. 37?41, October, 1983.
4. J.W. Lloyd,Foundations of Logic Programming, 2nd ed. Springer-Verlag, 1987.
5. J.W. Lloyd, ?Logic as a foundation for deductive database systems,? inProceedings of IFIP Conference on Information Processing, San Francisco, August 1989, pp. 323?324.