@article{PPN592509036+DMDLOG_0002, title = {Vorwort zur Planimetrie.}, booktitle = {Planimetrie Theil 2}, series = {GDML\_Books}, publisher = {Hirt}, address = {Breslau}, year = {1877}, pages = {III}, url = {http://dml.mathdoc.fr/item/PPN592509036+DMDLOG_0002} }
(éd.). Vorwort zur Planimetrie., dans Planimetrie Theil 2, GDML_Books, (1877), p. III. http://gdmltest.u-ga.fr/item/PPN592509036+DMDLOG_0002/