1. A theory of asynchronous control networks;Bruno;IEEE Trans. Comput.,1971
2. Marked directed graphs;Commoner;J. Comput. System Sci.,1971
3. Analysis of Production Schemata by Petri Nets;Hack,1972
4. Decidability Questions for Petri Nets;Hack,1975
5. Petri Net Languages;Hack,1976