Henning Dierks Sebastian Kupferschmid Kim Guldstrand Larsen Automatic Abstraction Refinement for Timed Automata. 114-129 2007 conf/formats/2007 FORMATS http://dx.doi.org/10.1007/978-3-540-75454-1_10 db/conf/formats/formats2007.html#DierksKL07