Observations of Natural ELF and VLF Electromagnetic Noises by Using Ball Antennas Ogawa, Toshio ; Tanaka, Yoshikazu ; Miura, Teruo ; Yasuhara, Michihiro Abstract Publication: Journal of Geomagnetism and Geoelectricity Pub Date: 1966 DOI: 10.5636/jgg.18.443 Bibcode: 1966JGG....18..443O