@article{PPN379157292+dmdlog11, title = {\S\ 4. Trennungsaxiome: T0- und T1-R\"aume.}, booktitle = {Topologie Bd. 1}, series = {GDML\_Books}, year = {1935}, pages = {58}, url = {http://dml.mathdoc.fr/item/PPN379157292+dmdlog11} }
(éd.). § 4. Trennungsaxiome: T0- und T1-Räume., dans Topologie Bd. 1, GDML_Books, (1935), p. 58. http://gdmltest.u-ga.fr/item/PPN379157292+dmdlog11/