Dario Campagna Carla Piazza Hybrid Automata in Systems Biology: How Far Can We Go? 93-108 2009 229 Electr. Notes Theor. Comput. Sci. 1 http://dx.doi.org/10.1016/j.entcs.2009.02.007 db/journals/entcs/entcs229.html#CampagnaP09