@article{oai:repository.dl.itc.u-tokyo.ac.jp:00034494, author = {Sezawa, Katsutada and Kanai, Kiyoshi}, issue = {2}, journal = {東京帝國大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, Tokyo Imperial University}, month = {Jun}, pages = {208--232}, title = {18. On the Packet Velocity of Dispersive Elastic Waves of Irregular Form}, volume = {17}, year = {1939} }