@article{IM_1986__84_143349,
     author = {J.-H. Eschenburg},
     title = {Local convexity and nonnegative curvature - {Gromov's} proof of the sphere theorem.},
     journal = {Inventiones mathematicae},
     pages = {507--522},
     publisher = {mathdoc},
     volume = {84},
     year = {1986},
     zbl = {0594.53034},
     url = {http://geodesic.mathdoc.fr/item/IM_1986__84_143349/}
}