@article{10_4153_CJM_1968_134_x,
     author = {Klarner, David A.},
     title = {The {Number} of {-Coloured} {Graphs}},
     journal = {Canadian journal of mathematics},
     pages = {1344--1352},
     year = {1968},
     volume = {20},
     number = {1},
     doi = {10.4153/CJM-1968-134-x},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1968-134-x/}
}