@article{Silva_2008,
    doi = {10.1016/j.tcs.2008.09.031},
    url = {https://doi.org/10.1016%2Fj.tcs.2008.09.031},
    year = {2008},
    month = {dec},
    publisher = {Elsevier {BV}},
    volume = {409},
    number = {3},
    pages = {537--548},
    author = {Pedro V. Silva},
    title = {Rational subsets of partially reversible monoids},
    journal = {Theoretical Computer Science}
}

@article{Silva_2008, doi = {10.1016/j.tcs.2008.09.031}, url = {https://doi.org/10.1016%2Fj.tcs.2008.09.031}, year = {2008}, month = {dec}, publisher = {Elsevier {BV}}, volume = {409}, number = {3}, pages = {537--548}, author = {Pedro V. Silva}, title = {Rational subsets of partially reversible monoids}, journal = {Theoretical Computer Science} }