@article{10_4153_CMB_1969_051_5,
     author = {Erd\H{o}s, P.},
     title = {On {A} {Combinatorial} {Problem} {III}},
     journal = {Canadian mathematical bulletin},
     pages = {413--416},
     year = {1969},
     volume = {12},
     number = {4},
     doi = {10.4153/CMB-1969-051-5},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1969-051-5/}
}