In: Brauer, W.; Reisig, W.; Rozenberg, G.: Lecture Notes in Computer Science, Vol. 254: Petri Nets: Central Models and Their Properties, Advances in Petri Nets 1986, Part I, Proceedings of an Advanced Course, Bad Honnef, September 1986, pages 300-336. Springer-Verlag, 1987.
Also in: Jensen, K.; Rozenberg, G.: High Level Petri Nets, Theory and Application, pages 247-283. Springer-Verlag, 1991.