%0 Journal Article %A Gregório Pacelli Bessa %T Differentiable sphere theorems for Ricci curvature. %J Mathematische Zeitschrift %D 1993 %P 245-260 %V 214 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/MZ_1993__214_1_174566/ %F MZ_1993__214_1_174566