Romana, A. Geomagnetic data 1969 rapid variations A. Romana and D. Van Sabben - Paris International Union of Geodesy and Geophysics 1971 - viii+80p. - International Association of Geomagnetism and Aeronomy; No. 12x2 . Subjects--Topical Terms: Iaga Bulletin No.12x2Iaga Bulletin-dataIaga IndicesIugg Universal Decimal Class. No.: 550.38 / IAGA