1. Astronomical Observatory of Japan (ed) (2018) Chronological Scientific Tables 2019 (Rika Nenpyo 2019). Maruzen, Tokyo. (in Japanese)
2. Bockheim JG, Hartemink AE (2017) The Soils of Wisconsin, pp 393, Springer
3. Broecker WS (1984) Terminations. In: Berger A, Imbrie J, Hays J, Kukla G, Saltzman B (eds) Milankovitch and Climate, Reidel, Dordrecht, pp 687–698
4. Chiba T (1991) Hageyama no kenkyu (A study of bald mountains), revised edition. Sosiete, Tokyo (in Japanese)
5. Cho K (1986) Fundamental problems and conditions for expansion of upland farming. Jpn. J Farm Manage 23(3):4–17 (In Japanese)