@article{oai:repository.dl.itc.u-tokyo.ac.jp:00033498,
 author = {Ikegami, Ryohei},
 issue = {2},
 journal = {東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo},
 month = {Aug},
 note = {application/pdf},
 pages = {327--338},
 title = {On the Secular Variation of Magnitude-Frequency Relation of Earthquakes},
 volume = {45},
 year = {1967}
}