Rajeev Alur Costas Courcoubetis David L. Dill Model-Checking for Real-Time Systems conf/lics/LICS5 1990 conf/lics/1990 LICS 414-425 db/conf/lics/lics90.html#AlurCD90 http://dx.doi.org/10.1109/LICS.1990.113766