1. André, C.: "Behaviour of a Place-Transition net on a Subset of Transitions" in [Girault/Reisig 82], 1982
2. Baumgarten, B.: "On Internal and External Characterizations of PT-Net Building Block Behaviour", Proceedings of the 7th European Workshop on Application and Theory of Petri Nets, Oxford 1986
3. Best, E:;Devillers,R.: "Sequential and Concurrent Behaviour in Petri Net Theory", TCS Vol. 55, no. 1, 1987
4. Brauer, W.; Reisig, W.; Rozenberg, G.(eds.): "Petri Nets: Central Models and Their Properties", LNCS 254, 1987
5. Castellano, L.; De Michelis, G.; Pomello, L.: "Concurrency vs. Interleaving: an Instructive Example", EATCS Bulletin 31, 1987