@article{JRAM_1973__0262_0263_151352,
     author = {H. Karzel and H.-J. Kroll and K. S\"orensen},
     title = {Invariante {Gruppenpartitionen} und {Doppelr\"aume.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {153--157},
     publisher = {mathdoc},
     volume = {0262_0263},
     year = {1973},
     zbl = {0265.50003},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1973__0262_0263_151352/}
}