@article{Karhum_ki_2011,
    doi = {10.1134/s0081543811060083},
    url = {https://doi.org/10.1134%2Fs0081543811060083},
    year = {2011},
    month = {oct},
    publisher = {Pleiades Publishing Ltd},
    volume = {274},
    number = {1},
    pages = {116--123},
    author = {Juhani Karhumäki and Aleksi Saarela},
    title = {On maximal chains of systems of word equations},
    journal = {Proceedings of the Steklov Institute of Mathematics}
}

@article{Karhum_ki_2011, doi = {10.1134/s0081543811060083}, url = {https://doi.org/10.1134%2Fs0081543811060083}, year = {2011}, month = {oct}, publisher = {Pleiades Publishing Ltd}, volume = {274}, number = {1}, pages = {116--123}, author = {Juhani Karhumäki and Aleksi Saarela}, title = {On maximal chains of systems of word equations}, journal = {Proceedings of the Steklov Institute of Mathematics} }