@article{PPN517627655+dmdlog30, title = {91. Der Erdmagnetismus.}, booktitle = {Das Weltsystem Theil 2}, series = {GDML\_Books}, year = {1896}, pages = {126}, url = {http://dml.mathdoc.fr/item/PPN517627655+dmdlog30} }
(éd.). 91. Der Erdmagnetismus., dans Das Weltsystem Theil 2, GDML_Books, (1896), p. 126. http://gdmltest.u-ga.fr/item/PPN517627655+dmdlog30/