@article{1183496194, author = {Cummings, Louise D.}, title = {Heptagonal systems of eight lines in a plane}, journal = {Bull. Amer. Math. Soc.}, volume = {38}, number = {12}, year = {1932}, pages = { 700-702}, language = {en}, url = {http://dml.mathdoc.fr/item/1183496194} }
Cummings, Louise D. Heptagonal systems of eight lines in a plane. Bull. Amer. Math. Soc., Tome 38 (1932) no. 12, pp. 700-702. http://gdmltest.u-ga.fr/item/1183496194/