Susanna Donatelli H. C. M. Kleijn Application and Theory of Petri Nets 1999, 20th International Conference, ICATPN '99, Williamsburg, Virginia, USA, June 21-25, 1999, Proceedings ICATPN Lecture Notes in Computer Science 1639 Springer 1999 3-540-66132-8 db/conf/apn/icatpn99.html