Neil D. Jones, Lawrence H. Landweber, Y. Edmund Lien. Complexity of Some Problems in Petri Nets. Theoretical Computer Science, 4(3):277-299, 1977.
@article{JonesLL77, title = {Complexity of Some Problems in Petri Nets}, author = {Neil D. Jones and Lawrence H. Landweber and Y. Edmund Lien}, year = {1977}, researchr = {https://researchr.org/publication/JonesLL77}, cites = {0}, citedby = {0}, journal = {Theoretical Computer Science}, volume = {4}, number = {3}, pages = {277-299}, }