APA-referens (7:e uppl.)

Semple, E. C., & Ratzel, F. (1911). Influences of geographic environment, on the basis of Ratzel's system of anthropo-geography. H. Holt and Co..

Chicago-referens (17:e uppl.)

Semple, Ellen Churchill, och Friedrich Ratzel. Influences of Geographic Environment, on the Basis of Ratzel's System of Anthropo-geography. New York: H. Holt and Co., 1911.

MLA-referens (8:e uppl.)

Semple, Ellen Churchill, och Friedrich Ratzel. Influences of Geographic Environment, on the Basis of Ratzel's System of Anthropo-geography. H. Holt and Co., 1911.