1. K. Apt. Logic programming. In J. van Leeuven, editor, Handbook of theoretical computer science, pages 493–574. Elsevier, Amsterdam, 1990.
2. R.J. Bayardo, Jr and R.C. Schrag. Using CSP look-back techniques to solve real-world SAT instances. In Proceedings of the Fourteenth National Conference on Artificial Intelligence (AAAI-97). MIT Press, 1997.
3. K.L. Clark. Negation as failure. In H. Gallaire and J. Minker, editors, Logic and data bases, pages 293–322. Plenum Press, New York-London, 1978.
4. T. Eiter, N. Leone, C. Mateis, G. Pfeifer, and F. Scarcello. AKR system dlv: Progress report, comparisons and benchmarks. In Proceeding of the Sixth International Conference on Knowledge Representation and Reasoning (KR’ 98), pages 406–417. Morgan Kaufmann, 1998.
5. M.R. Garey and D.S. Johnson. Computers and intractability. A guide to the theory of NP-completeness. W.H. Freeman and Co., San Francisco, Calif., 1979.