@article{GDZPPN002090880,
title = {Group Actions and Curvature.},
journal = {Inventiones mathematicae},
volume = {27},
year = {1974},
pages = {31-48},
zbl = {0271.53044},
url = {http://dml.mathdoc.fr/item/GDZPPN002090880}
}
Grove, K.; Karcher, H.; Ruh, E.A. Group Actions and Curvature.. Inventiones mathematicae, Tome 27 (1974) pp. 31-48. http://gdmltest.u-ga.fr/item/GDZPPN002090880/