Serenella Cerrito Marta Cialdea Mayer Free-Variable Tableaux for Constant-Domain Quantified Modal Logics with Rigid and Non-rigid Designation. 137-151 2001 conf/cade/2001 IJCAR http://link.springer.de/link/service/series/0558/bibs/2083/20830137.htm db/conf/cade/ijcar2001.html#CerritoM01