Takakuwa, Y. & Koike, H. & Narita, K. (2009)
Outline of fossil elasmobranchs from the Middle Miocene Bessho and Aoki Formations, Nagano Prefecture, Japan. [in Japanese with English abstract] Research Report of the Shinshushinmachi Fossil Museum, 13, 7–18
Koike, H. & Ohe, F. & Narita, K. (2008)
A fossil dermal denticle, Scymnodon ichiharai (Elasmobranchii; Somniosidae) from Miocene Bessho Formation in Azumino City, Nagano Prefecture, Japan. [in Japanese with English abstract] Research Report of the Shinshushinmachi Fossil Museum, 11, 1–13
Koike, H. & Ohe, F. & Narita, K. (2008)
A fossil dermal denticle, Etmopterus sp. (Elasmobranchii; Etmopteridae) from the Middle Miocene Bessho Formation in Azumino City, Nagano Prefecture, Japan. [in Japanese with English abstract] Research Report of the Shinshushinmachi Fossil Museum, 11, 15–18