@article{10_4153_CJM_1968_054_x,
     author = {Sobczyk, Andrew},
     title = {Graph-Colouring and {Combinatorial} {Numbers}},
     journal = {Canadian journal of mathematics},
     pages = {520--534},
     year = {1968},
     volume = {20},
     number = {1},
     doi = {10.4153/CJM-1968-054-x},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1968-054-x/}
}