Não informado. (1921). Contribution from the Institute of Geology and Paleontology. Tohoku University.
Chicago-referens (17:e uppl.)Não informado. Contribution from the Institute of Geology and Paleontology. Sendai, Japão: Tohoku University, 1921.
MLA-referens (8:e uppl.)Não informado. Contribution from the Institute of Geology and Paleontology. Tohoku University, 1921.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.