@article{10_4153_CMB_1986_067_8,
     author = {Fawcett, Barry},
     title = {A {Categorical} {Characterization} of the {Four} {Colour} {Theorem}},
     journal = {Canadian mathematical bulletin},
     pages = {426--431},
     year = {1986},
     volume = {29},
     number = {4},
     doi = {10.4153/CMB-1986-067-8},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1986-067-8/}
}