@article{Lipton_1977,
    doi = {10.1145/322017.322031},
    url = {https://doi.org/10.1145%2F322017.322031},
    year = {1977},
    month = {jul},
    publisher = {Association for Computing Machinery ({ACM})},
    volume = {24},
    number = {3},
    pages = {522--526},
    author = {Richard J. Lipton and Yechezkel Zalcstein},
    title = {Word Problems Solvable in Logspace},
    journal = {Journal of the {ACM}}
}

@article{Lipton_1977, doi = {10.1145/322017.322031}, url = {https://doi.org/10.1145%2F322017.322031}, year = {1977}, month = {jul}, publisher = {Association for Computing Machinery ({ACM})}, volume = {24}, number = {3}, pages = {522--526}, author = {Richard J. Lipton and Yechezkel Zalcstein}, title = {Word Problems Solvable in Logspace}, journal = {Journal of the {ACM}} }