@article{Maciel_2000,
    doi = {10.1016/s0304-3975(99)00278-9},
    url = {https://doi.org/10.1016%2Fs0304-3975%2899%2900278-9},
    year = {2000},
    month = {aug},
    publisher = {Elsevier {BV}},
    volume = {245},
    number = {1},
    pages = {135--148},
    author = {Alexis Maciel and Pierre P{\'{e}}ladeau and Denis Th{\'{e}}rien},
    title = {Programs over semigroups of dot-depth one},
    journal = {Theoretical Computer Science}
}

@article{Maciel_2000, doi = {10.1016/s0304-3975(99)00278-9}, url = {https://doi.org/10.1016%2Fs0304-3975%2899%2900278-9}, year = {2000}, month = {aug}, publisher = {Elsevier {BV}}, volume = {245}, number = {1}, pages = {135--148}, author = {Alexis Maciel and Pierre P{\'{e}}ladeau and Denis Th{\'{e}}rien}, title = {Programs over semigroups of dot-depth one}, journal = {Theoretical Computer Science} }