@article{JRAM_1961__208_150502,
     author = {Gilbert Helmberg},
     title = {Topologische {Untergruppenr\"aume.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {164--180},
     publisher = {mathdoc},
     volume = {208},
     year = {1961},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1961__208_150502/}
}