Koda, Y. & Koike, W. & Ando, H. & Uyeno, T. & Usui, K. (2007)
Carcharodon megalodon tooth set collected from calcareous concretions in the Miocene Kokozura Formation, Takaku Group, Kitaibaraki city, Ibaraki Prefecture, Japan. Palaeontological Society of Japan, 81: 1–2