1. Rabin's proof of the undecidability of the reachability set inclusion problem of vector addition systems;Baker,1973
2. Analysis of production schemata by Petri nets;Hack,1972
3. Analysis of production schemata by Petri nets;Hack,1974
4. Decision problems for Petri nets and vector addition systems;Hack,1975
5. The recursive equivalence of the reachability problem and the liveness problem for Petri nets and vector addition systems;Hack;Proc. 15th Annual IEEE Symposium on Switching and Automata Theory,1974