1. On the decision problem for formulas in which all disjunctions are binary;Aanderaa;Proc. 2nd Scandinavian Logic Symp.,1971
2. Cycle unification;Bibel,1992
3. Flow diagrams, Turing machines and languages with only two formation rules;Böhm;Comm. ACM,1966
4. Reduktionstypen in Krom- und Hornformeln;Börger,1971
5. A practical technique for detecting non-terminating queries for a restricted class of Horn clauses, using directed, weighted graphs;DeSchreye;Proc. Internat. Conf. on Logic Programming,1990