Domenico Cantone, Marianna Nicolosi Asmundo. A Further and Effective Liberalization of the delta-Rule in Free Variable Semantic Tableaux. In Ricardo Caferra, Gernot Salzer, editors, Automated Deduction in Classical and Non-Classical Logics, Selected Papers. Volume 1761 of Lecture Notes in Computer Science, pages 109-125, Springer, 1998. [doi]
Abstract is missing.