8Gotoh, K., Akinaga, Y., Hayakawa, M., etal. Principal component analysis of ULF geomagneticdata for Izu islands earthquakes in July [J]. J. Atmos. Electr.2000. 22, 1-12.
9Hattori K, Serita A , Gotoh K.U LF geomagnetic anomaly associated with 2000 Izu Islands earthquake swarm[J]. Japan.Physics and Chemistry Or the Earth, 2004, 29 (49): 425: 435.
