1. Artificial Intelligence and Computational Logic;F. Arcelli,1999
2. Baldwin, J.F., Martin, T.P., Pilsworth, B.W.: Fril- Fuzzy and Evidential Reasoning in Artificial Intelligence. John Wiley & Sons, Inc., Chichester (1995)
3. Guerrero, J.A., Moreno, G.: Optimizing fuzzy logic programs by unfolding, aggregation and folding. ENTCS (Elsevier Science) 219, 19–34 (2008)
4. Hanus, M. (ed.): Curry: An Integrated Functional Logic Language (2003),
http://www.informatik.uni-kiel.de/~mh/curry
5. Ishizuka, M., Kanai, N.: Prolog-ELF Incorporating Fuzzy Logic. In: Joshi, A.K. (ed.) Proc. of IJCAI 1985, pp. 701–703. Morgan Kaufmann, San Francisco (1985)