1. Introduction to logic programming;Apt,1990
2. On the correctness of Unfold/Fold transformation of normal and extended logic programs;Aravidan,1993
3. Transforming constraint logic programs;Bensaou,1994
4. Differential logic programming;Bossi,1993
5. Basic transformation operations which preserve computed answer substitutions of logic programs;Bossi;J. Logic Programming,1993