1. Cycle unification;Bibel,1992
2. Recurrence domains: their unification and application to logic programming;Chen,1991
3. Yet another intelligent Backtracking method;Codognet;Proc. ICLP/SL,1988
4. Prolog II, Manuels de Reference;Colmerauer,1979
5. Equations and inequations on finite and infinite trees;Colmerauer;Proc. FGCS'84,1984