@article{1183504870, author = {Springer, C. E.}, title = {Dual geodesics on a surface}, journal = {Bull. Amer. Math. Soc.}, volume = {48}, number = {12}, year = {1942}, pages = { 901-906}, language = {en}, url = {http://dml.mathdoc.fr/item/1183504870} }
Springer, C. E. Dual geodesics on a surface. Bull. Amer. Math. Soc., Tome 48 (1942) no. 12, pp. 901-906. http://gdmltest.u-ga.fr/item/1183504870/