Nikaido, A. & Kikuchi, Y. (1983)
Some vertebrae of sharks from the Miocene Nawashiroda Formation, Ibaraki Prefecture, northeast Japan. Journal of the Geological Society of Japan, 89(5), 299–301
Kikuchi, Y. & Takaoka, Y. (1979)
Discovery of the fossil gill raker of a basking shark from the Tertiary system in Chichibu Basin, Saitama Prefecture. Journal of the Geological Society of Japan, 85(2), 97–98