@article{700990,
title = {Topologische Untergruppenra\"ume},
booktitle = {General Topology and its Relations to Modern Analysis and Algebra},
series = {GDML\_Books},
publisher = {Academia Publishing House of the Czechoslovak Academy of Sciences},
address = {Praha},
year = {1962},
pages = {196-198},
mrnumber = {MR0173727},
zbl = {0111.31103},
url = {http://dml.mathdoc.fr/item/700990}
}
Helmberg, G. Topologische Untergruppenraüme, dans General Topology and its Relations to Modern Analysis and Algebra, GDML_Books, (1962), pp. 196-198. http://gdmltest.u-ga.fr/item/700990/