@article{Mostowski_1991,
    doi = {10.1016/0304-3975(91)90283-8},
    url = {https://doi.org/10.1016%2F0304-3975%2891%2990283-8},
    year = {1991},
    month = {jun},
    publisher = {Elsevier {BV}},
    volume = {83},
    number = {2},
    pages = {323--335},
    author = {A.W. Mostowski},
    title = {Hierarchies of weak automata and weak monadic formulas},
    journal = {Theoretical Computer Science}
}

@article{Mostowski_1991, doi = {10.1016/0304-3975(91)90283-8}, url = {https://doi.org/10.1016%2F0304-3975%2891%2990283-8}, year = {1991}, month = {jun}, publisher = {Elsevier {BV}}, volume = {83}, number = {2}, pages = {323--335}, author = {A.W. Mostowski}, title = {Hierarchies of weak automata and weak monadic formulas}, journal = {Theoretical Computer Science} }