Bartels, Julius Geomagnetic data 1960 rapid variations Julius Bartels, A. Romana and J. Veldkamp - Paris International Union of Geodesy and Geophysics 1964 - vi+64p. - International Association of Geomagnetism and Aeronomy; No. 12o2 . Subjects--Topical Terms: Iaga Bulletin No.12o2Iaga Bulletin-dataIaga IndicesIugg Universal Decimal Class. No.: 550.38 / IAGA