@article{GDZPPN002067102,
title = {Rigidity of convex domains in manifolds with nonnegative Ricci and sectional curvature.},
journal = {Commentarii mathematici Helvetici},
volume = {64},
year = {1989},
pages = {173-186},
zbl = {0692.53020},
url = {http://dml.mathdoc.fr/item/GDZPPN002067102}
}
Schroeder, Viktor; Strake, Martin. Rigidity of convex domains in manifolds with nonnegative Ricci and sectional curvature.. Commentarii mathematici Helvetici, Tome 64 (1989) pp. 173-186. http://gdmltest.u-ga.fr/item/GDZPPN002067102/