@article{Esparza:FI:1997,
    doi = {10.3233/fi-1997-3112},
    url = {https://doi.org/10.3233%2Ffi-1997-3112},
    year = {1997},
    publisher = {{IOS} Press},
    volume = {31},
    number = {1},
    pages = {13--25},
    author = {Javier Esparza},
    title = {Petri Nets, Commutative Context-Free Grammars, and Basic Parallel Processes},
    journal = {Fundamenta Informaticae}
}

@article{Esparza:FI:1997, doi = {10.3233/fi-1997-3112}, url = {https://doi.org/10.3233%2Ffi-1997-3112}, year = {1997}, publisher = {{IOS} Press}, volume = {31}, number = {1}, pages = {13--25}, author = {Javier Esparza}, title = {Petri Nets, Commutative Context-Free Grammars, and Basic Parallel Processes}, journal = {Fundamenta Informaticae} }