Citazione Stile APA (7a Edizione)

Van Valkenburg, S., & Erickson, F. C. (1939). Elements of political geography. Prentice-Hall.

Citazione stile Chigago Style (17a edizione)

Van Valkenburg, Samuel, e Franklin C. Erickson. Elements of Political Geography. New York: Prentice-Hall, 1939.

Citatione MLA (9a ed.)

Van Valkenburg, Samuel, e Franklin C. Erickson. Elements of Political Geography. Prentice-Hall, 1939.