@book{PPN379157292, title = {Topologie Bd. 1}, series = {GDML\_Books}, year = {1935}, language = {ger}, url = {http://dml.mathdoc.fr/item/PPN379157292} }
(éd.). Topologie Bd. 1. GDML_Books (1935), http://gdmltest.u-ga.fr/item/PPN379157292/