Drag-out effect of piezomagnetic signals due to a borehole: The Mogi source as an example - Sasai, Y.; Johnston, M.J.S.; Tanaka, Y.; Mueller, R.; Hashimoto, T.; Utsugi, M.; Sakanaka, S.; Uyeshima, M.; Zlotnicki, J.; Yvetot, P. (Annals of Geophysics, 2007)