@article{Robertson_1984,
    doi = {10.1016/0095-8956(84)90013-3},
    url = {https://doi.org/10.1016%2F0095-8956%2884%2990013-3},
    year = {1984},
    month = {feb},
    publisher = {Elsevier {BV}},
    volume = {36},
    number = {1},
    pages = {49--64},
    author = {Neil Robertson and P.D Seymour},
    title = {Graph minors. {III}. Planar tree-width},
    journal = {Journal of Combinatorial Theory, Series B}
}

@article{Robertson_1984, doi = {10.1016/0095-8956(84)90013-3}, url = {https://doi.org/10.1016%2F0095-8956%2884%2990013-3}, year = {1984}, month = {feb}, publisher = {Elsevier {BV}}, volume = {36}, number = {1}, pages = {49--64}, author = {Neil Robertson and P.D Seymour}, title = {Graph minors. {III}. Planar tree-width}, journal = {Journal of Combinatorial Theory, Series B} }