@article{oai:repository.dl.itc.u-tokyo.ac.jp:00051814,
 author = {Utada, Hisashi},
 issue = {1},
 journal = {東京大学地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo},
 month = {},
 pages = {1--14},
 title = {Plane-wave and Flat Earth Approximations in Natural-source Electromagnetic Induction Studies},
 volume = {93},
 year = {2018}
}