@article{ELDER_2008,
    doi = {10.1142/s0218196708004901},
    url = {https://doi.org/10.1142%2Fs0218196708004901},
    year = {2008},
    month = {dec},
    publisher = {World Scientific Pub Co Pte Lt},
    volume = {18},
    number = {08},
    pages = {1345--1364},
    author = {MURRAY ELDER and MARK KAMBITES and GRETCHEN OSTHEIMER},
    title = {{ON} {GROUPS} {AND} {COUNTER} {AUTOMATA}},
    journal = {International Journal of Algebra and Computation}
}

@article{ELDER_2008, doi = {10.1142/s0218196708004901}, url = {https://doi.org/10.1142%2Fs0218196708004901}, year = {2008}, month = {dec}, publisher = {World Scientific Pub Co Pte Lt}, volume = {18}, number = {08}, pages = {1345--1364}, author = {MURRAY ELDER and MARK KAMBITES and GRETCHEN OSTHEIMER}, title = {{ON} {GROUPS} {AND} {COUNTER} {AUTOMATA}}, journal = {International Journal of Algebra and Computation} }