Brauer, W.; Rozenberg, G.; Salomaa, A.: EATCS Monographs on Theoretical Computer Science, Vol. 13. Springer Verlag, 1988.
Abstract: Petri net theory provides a formal basis for describing and reasoning about concurrent systems. It proposes the use of partially ordered sets in order to describe the behaviour of concurrent sytems. This book contains a detailed mathematical treatment of the approach. It deals with partial orderings and shows how ``occurrence nets'' are used to model the executions of concurrent systems.