@article{1183495753,
author = {Cummings, Louise D.},
title = {Hexagonal systems of seven lines in a plane},
journal = {Bull. Amer. Math. Soc.},
volume = {38},
number = {12},
year = {1932},
pages = { 105-110},
language = {en},
url = {http://dml.mathdoc.fr/item/1183495753}
}
Cummings, Louise D. Hexagonal systems of seven lines in a plane. Bull. Amer. Math. Soc., Tome 38 (1932) no. 12, pp. 105-110. http://gdmltest.u-ga.fr/item/1183495753/