@article{Kolaitis_2000,
    doi = {10.1006/jcss.2000.1713},
    url = {https://doi.org/10.1006%2Fjcss.2000.1713},
    year = {2000},
    month = {oct},
    publisher = {Elsevier {BV}},
    volume = {61},
    number = {2},
    pages = {302--332},
    author = {Phokion G. Kolaitis and Moshe Y. Vardi},
    title = {Conjunctive-Query Containment and Constraint Satisfaction},
    journal = {Journal of Computer and System Sciences}
}

@article{Kolaitis_2000, doi = {10.1006/jcss.2000.1713}, url = {https://doi.org/10.1006%2Fjcss.2000.1713}, year = {2000}, month = {oct}, publisher = {Elsevier {BV}}, volume = {61}, number = {2}, pages = {302--332}, author = {Phokion G. Kolaitis and Moshe Y. Vardi}, title = {Conjunctive-Query Containment and Constraint Satisfaction}, journal = {Journal of Computer and System Sciences} }