@article{Robertson_1983,
    doi = {10.1016/0095-8956(83)90079-5},
    url = {https://doi.org/10.1016%2F0095-8956%2883%2990079-5},
    year = {1983},
    month = {aug},
    publisher = {Elsevier {BV}},
    volume = {35},
    number = {1},
    pages = {39--61},
    author = {Neil Robertson and P.D. Seymour},
    title = {Graph minors. I. Excluding a forest},
    journal = {Journal of Combinatorial Theory, Series B}
}

@article{Robertson_1983, doi = {10.1016/0095-8956(83)90079-5}, url = {https://doi.org/10.1016%2F0095-8956%2883%2990079-5}, year = {1983}, month = {aug}, publisher = {Elsevier {BV}}, volume = {35}, number = {1}, pages = {39--61}, author = {Neil Robertson and P.D. Seymour}, title = {Graph minors. I. Excluding a forest}, journal = {Journal of Combinatorial Theory, Series B} }