@article{10_4153_CMB_1970_071_3,
     author = {Hell, Pavol and Ne\v{s}et\v{r}il, Jaroslav},
     title = {Graphs and {k-Societies}},
     journal = {Canadian mathematical bulletin},
     pages = {375--381},
     year = {1970},
     volume = {13},
     number = {3},
     doi = {10.4153/CMB-1970-071-3},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1970-071-3/}
}