Parosh Aziz Abdulla Pritha Mahata Richard Mayr Dense-Timed Petri Nets: Checking Zenoness, Token liveness and Boundedness. 2007 3 Logical Methods in Computer Science 1 http://dx.doi.org/10.2168/LMCS-3(1:1)2007 db/journals/lmcs/lmcs3.html#AbdullaMM07