@article{oai:repository.dl.itc.u-tokyo.ac.jp:00033412,
 author = {Yoshiyama, Ryoichi},
 issue = {5},
 journal = {東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo},
 month = {Dec},
 note = {application/pdf},
 pages = {993--1000},
 title = {49. Note on the Second Derivative of Time-Distance Curve},
 volume = {46},
 year = {1968}
}