@article{MOMA_1967__71_177383,
     author = {Rolf Schneider},
     title = {Eine allgemeine {Extremaleigenschaft} der {Kugel.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {231--237},
     publisher = {mathdoc},
     volume = {71},
     year = {1967},
     zbl = {0168.43401},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1967__71_177383/}
}