Ogawa, Y., Ujihara, N., S., Tank, S.B., Honkura, Y., Onizawa, S., Mori, T., Makino, M., “ Two Electrical Conductors Beneath Kusatsu-Shirane Volcano, Japan, Imaged by Audiomagnetotellurics, and Their Implications for the Hydrothermal System”, Earth Planets Space, 58, 1053–1059, 2006.