1. Hack, M. Petri net languages. — TR-159, MIT Lab. Computer Science, Cambridge, Mass., 1976, 128 p.
2. Lecture Notes in Computer Science;V.E. Kotov,1978
3. Hack, M. Decision problems for Petri nets and vector addition systems. — MAC-TM-59, Project MAC, MIT, 1975, 79 p.
4. Kosarajn, S.R. Limitations of Dijkstra's semaphore primitives and Petri nets. — Operating Systems Review, 1973, 7, no.4, p. 122–136.
5. Hack, M. Decidability questions for Petri nets. — TR-161, MIT Lab. Computer Science, Cambridge, Mass., 1976, 194 p.