@article{1183507348, author = {Springer, C. E.}, title = {Union curves and union curvature}, journal = {Bull. Amer. Math. Soc.}, volume = {51}, number = {11}, year = {1945}, pages = { 686-691}, language = {en}, url = {http://dml.mathdoc.fr/item/1183507348} }
Springer, C. E. Union curves and union curvature. Bull. Amer. Math. Soc., Tome 51 (1945) no. 11, pp. 686-691. http://gdmltest.u-ga.fr/item/1183507348/