@article{10_1017_S0008439500024310,
     author = {Erd\"os, P.},
     title = {Solution by {P.} {J.} {Ryan,} {University} of {Toronto}},
     journal = {Canadian mathematical bulletin},
     pages = {112--112},
     year = {1965},
     volume = {8},
     number = {1},
     doi = {10.1017/S0008439500024310},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0008439500024310/}
}