@article{1183536278,
author = {Clarke, Frank H.},
title = {Maximum principles without differentiability},
journal = {Bull. Amer. Math. Soc.},
volume = {81},
number = {4},
year = {1975},
pages = { 219-222},
language = {en},
url = {http://dml.mathdoc.fr/item/1183536278}
}
Clarke, Frank H. Maximum principles without differentiability. Bull. Amer. Math. Soc., Tome 81 (1975) no. 4, pp. 219-222. http://gdmltest.u-ga.fr/item/1183536278/