Mireille E. Broucke Maria Domenica Di Benedetto Alberto L. Sangiovanni-Vincentelli Stefano Di Gennaro Theory of Optimal Control Using Bisimulations. 89-102 http://link.springer.de/link/service/series/0558/bibs/1790/17900089.htm 2000 conf/hybrid/2000 HSCC db/conf/hybrid/hscc2000.html#BrouckeBSG00