@article{1261060588,
author = {OBATA, Morio},
title = {Certain conditions for a Riemannian manifold to be isometric with a sphere},
journal = {J. Math. Soc. Japan},
volume = {14},
number = {4},
year = {1962},
pages = { 333-340},
language = {en},
url = {http://dml.mathdoc.fr/item/1261060588}
}
OBATA, Morio. Certain conditions for a Riemannian manifold to be isometric with a sphere. J. Math. Soc. Japan, Tome 14 (1962) no. 4, pp. 333-340. http://gdmltest.u-ga.fr/item/1261060588/