Robert M. Fuhrer Bill Lin Steven M. Nowick Algorithms for the optimal state assignment of asynchronous state machines. 59-75 1995 conf/arvlsi/1995 ARVLSI http://doi.ieeecomputersociety.org/10.1109/ARVLSI.1995.515611 db/conf/arvlsi/arvlsi1995.html#FuhrerLN95