Bernhard Beckert, Rajeev Goré. Free Variable Tableaux for Propositional Modal Logics. In Didier Galmiche, editor, Automated Reasoning with Analytic Tableaux and Related Methods, International Conference, TABLEAUX 97, Pont-à-Mousson, France, May 13-16, 1997, Proceedings. Volume 1227 of Lecture Notes in Computer Science, pages 91-106, Springer, 1997.
Abstract is missing.