@article{Benedikt_2003,
    doi = {10.1145/876638.876642},
    url = {https://doi.org/10.1145%2F876638.876642},
    year = {2003},
    month = {sep},
    publisher = {Association for Computing Machinery ({ACM})},
    volume = {50},
    number = {5},
    pages = {694--751},
    author = {Michael Benedikt and Leonid Libkin and Thomas Schwentick and Luc Segoufin},
    title = {Definable relations and first-order query languages over strings},
    journal = {Journal of the {ACM}}
}

@article{Benedikt_2003, doi = {10.1145/876638.876642}, url = {https://doi.org/10.1145%2F876638.876642}, year = {2003}, month = {sep}, publisher = {Association for Computing Machinery ({ACM})}, volume = {50}, number = {5}, pages = {694--751}, author = {Michael Benedikt and Leonid Libkin and Thomas Schwentick and Luc Segoufin}, title = {Definable relations and first-order query languages over strings}, journal = {Journal of the {ACM}} }