@article{1183498694, author = {Morse, Marston}, title = {Three theorems on the envelope of extremals}, journal = {Bull. Amer. Math. Soc.}, volume = {42}, number = {12}, year = {1936}, pages = { 136-144}, language = {en}, url = {http://dml.mathdoc.fr/item/1183498694} }
Morse, Marston. Three theorems on the envelope of extremals. Bull. Amer. Math. Soc., Tome 42 (1936) no. 12, pp. 136-144. http://gdmltest.u-ga.fr/item/1183498694/