Susanna Donatelli, P. S. Thiagarajan: Petri Nets and Other Models of Concurrency - ICATPN 2006, 27th International Conference on Applications and Theory of Petri Nets and Other Models of Concurrency, Turku, Finland, June 26-30, 2006, Proceedings. Lecture Notes in Computer Science 4024, Springer 2006, ISBN 3-540-34699-6