Nikola Benes Jan Kretínský Kim Guldstrand Larsen Jirí Srba Checking Thorough Refinement on Modal Transition Systems Is EXPTIME-Complete. 112-126 2009 ICTAC http://dx.doi.org/10.1007/978-3-642-03466-4_7 conf/ictac/2009 db/conf/ictac/ictac2009.html#BenesKLS09