@article{CMUC_1993__34_3_a6,
     author = {Beltagy, M.},
     title = {Sufficient conditions for convexity in manifolds without focal points},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {443--449},
     publisher = {mathdoc},
     volume = {34},
     number = {3},
     year = {1993},
     mrnumber = {1243076},
     zbl = {0797.53034},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1993__34_3_a6/}
}