Patricia Bouyer Thomas Brihaye Véronique Bruyère Jean-François Raskin On the optimal reachability problem of weighted timed automata. 135-175 2007 31 Formal Methods in System Design 2 http://dx.doi.org/10.1007/s10703-007-0035-4 db/journals/fmsd/fmsd31.html#BouyerBBR07