Application and Theory of Petri Nets 1999 20th International Conference, ICATPN'99, Williamsburg, Virginia, USA, June 21-25, 1999 Proceedings - Donatelli, Susanna; Donatelli, Susanna; Kleijn, Jetty; Kleijn, Jetty (Springer Berlin Heidelberg : Imprint: Springer, 1999)