@article{MAN_1965__159_182696,
     author = {S. GUBER},
     title = {\"Uber die {Konvexit\"at} von {Verbandskegeln.}},
     journal = {Mathematische Annalen},
     pages = {356--364},
     year = {1965},
     volume = {159},
     url = {http://geodesic.mathdoc.fr/item/MAN_1965__159_182696/}
}