@article{JRAM_1950__187_150172,
     author = {Hans-Heinrich Ostmann},
     title = {\"Uber die {Anzahl} der {Elemente} von {Summenmengen.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {222--230},
     publisher = {mathdoc},
     volume = {187},
     year = {1950},
     zbl = {0039.27401},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1950__187_150172/}
}