@article{JRAM_1969__237_150944,
     author = {Richard Warlimont},
     title = {Konvexit\"at starker {Mittel.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {56--62},
     publisher = {mathdoc},
     volume = {237},
     year = {1969},
     zbl = {0174.09501},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1969__237_150944/}
}