@book{PPN236060120, title = {Varia. Atlas des Erdmagnetismus Bd. 12}, series = {GDML\_Books}, year = {1929}, language = {lat}, url = {http://dml.mathdoc.fr/item/PPN236060120} }
(éd.). Varia. Atlas des Erdmagnetismus Bd. 12. GDML_Books (1929), http://gdmltest.u-ga.fr/item/PPN236060120/