@article{1214431961,
author = {Chen, Bang-yen and Yano, Kentaro},
title = {Umbilical submanifolds with respect to a nonparallel normal direction},
journal = {J. Differential Geom.},
volume = {8},
number = {3},
year = {1973},
pages = { 589-597},
language = {en},
url = {http://dml.mathdoc.fr/item/1214431961}
}
Chen, Bang-yen; Yano, Kentaro. Umbilical submanifolds with respect to a nonparallel normal direction. J. Differential Geom., Tome 8 (1973) no. 3, pp. 589-597. http://gdmltest.u-ga.fr/item/1214431961/