Alessandro Cimatti Luigi Palopoli Yusi Ramadian Symbolic Computation of Schedulability Regions Using Parametric Timed Automata. 80-89 2008 RTSS http://doi.ieeecomputersociety.org/10.1109/RTSS.2008.36 conf/rtss/2008 db/conf/rtss/rtss2008.html#CimattiPR08