Gianfranco Balbo Massimiliano De Pierro Giuliana Franceschinis Tagged Generalized Stochastic Petri Nets. 1-15 2009 EPEW http://dx.doi.org/10.1007/978-3-642-02924-0_1 conf/epew/2009 db/conf/epew/epew2009.html#BalboPF09