APA (7e ed.) Bronvermelding

De Blij, H. J. (1967). Systematic political geography. Wiley.

Chicago (17e ed.) Bronvermelding

De Blij, Harm J. Systematic Political Geography. New York: Wiley, 1967.

MLA (9e ed.) Bronvermelding

De Blij, Harm J. Systematic Political Geography. Wiley, 1967.