@book{PPN237821559, title = {Gesammelte Abhandlungen Bd. 1}, series = {GDML\_Books}, year = {1932}, zbl = {58.0048.03}, language = {ger}, url = {http://dml.mathdoc.fr/item/PPN237821559} }
(éd.). Gesammelte Abhandlungen Bd. 1. GDML_Books (1932), http://gdmltest.u-ga.fr/item/PPN237821559/