Ian Hodkinson Angelo Montanari Guido Sciavicco Non-finite Axiomatizability and Undecidability of Interval Temporal Logics with C, D, and T. 308-322 2008 CSL http://dx.doi.org/10.1007/978-3-540-87531-4_23 conf/csl/2008 db/conf/csl/csl2008.html#HodkinsonMS08