@article{1183423358,
author = {Cummings, Louise D. and White, H. S.},
title = {Groupless triad systems on fifteen elements},
journal = {Bull. Amer. Math. Soc.},
volume = {22},
number = {3},
year = {1915},
pages = { 12-16},
language = {en},
url = {http://dml.mathdoc.fr/item/1183423358}
}
Cummings, Louise D.; White, H. S. Groupless triad systems on fifteen elements. Bull. Amer. Math. Soc., Tome 22 (1915) no. 3, pp. 12-16. http://gdmltest.u-ga.fr/item/1183423358/