Frank S. de Boer Maurizio Gabbrielli Maria Chiara Meo Proving Correctness of Timed Concurrent Constraint Programs. 37-51 2002 conf/fossacs/2002 FoSSaCS http://link.springer.de/link/service/series/0558/bibs/2303/23030037.htm db/conf/fossacs/fossacs2002.html#BoerGM02