Wienert, K. A. Notes on geomagnetic observatory and survey practice K. A. Wienert - Paris UNESCO 1970 - 217p. ISBN: 9231008161 Subjects--Topical Terms: Geomagnetic ObservatoryObservations,geomagneticObservatory-geomagnetic-setup Universal Decimal Class. No.: 550.380.2 / WIE