@article{McCallum_1988,
    doi = {10.1016/s0747-7171(88)80010-5},
    url = {https://doi.org/10.1016%2Fs0747-7171%2888%2980010-5},
    year = {1988},
    month = {feb},
    publisher = {Elsevier {BV}},
    volume = {5},
    number = {1-2},
    pages = {141--161},
    author = {Scott McCallum},
    title = {An improved projection operation for cylindrical algebraic decomposition of three-dimensional space},
    journal = {Journal of Symbolic Computation}
}

@article{McCallum_1988, doi = {10.1016/s0747-7171(88)80010-5}, url = {https://doi.org/10.1016%2Fs0747-7171%2888%2980010-5}, year = {1988}, month = {feb}, publisher = {Elsevier {BV}}, volume = {5}, number = {1-2}, pages = {141--161}, author = {Scott McCallum}, title = {An improved projection operation for cylindrical algebraic decomposition of three-dimensional space}, journal = {Journal of Symbolic Computation} }