@article{Shang_Zhi_1984,
    doi = {10.1016/0012-365x(84)90189-4},
    url = {https://doi.org/10.1016%2F0012-365x%2884%2990189-4},
    year = {1984},
    month = {feb},
    publisher = {Elsevier {BV}},
    volume = {48},
    number = {2-3},
    pages = {289--306},
    author = {Wang Shang-Zhi and Li Bo-Yu},
    title = {On the minimal cofinal subsets of a directed quasi-ordered set},
    journal = {Discrete Mathematics}
}

@article{Shang_Zhi_1984, doi = {10.1016/0012-365x(84)90189-4}, url = {https://doi.org/10.1016%2F0012-365x%2884%2990189-4}, year = {1984}, month = {feb}, publisher = {Elsevier {BV}}, volume = {48}, number = {2-3}, pages = {289--306}, author = {Wang Shang-Zhi and Li Bo-Yu}, title = {On the minimal cofinal subsets of a directed quasi-ordered set}, journal = {Discrete Mathematics} }