APA (7th ed.) Citation

Spahr, W. E. (1940). Economic principles and problems (4th ed.). Farrar & Rinehart, inc..

Chicago Style (17th ed.) Citation

Spahr, Walter E. Economic Principles and Problems. 4th ed. New York: Farrar & Rinehart, inc., 1940.

MLA (9th ed.) Citation

Spahr, Walter E. Economic Principles and Problems. 4th ed. Farrar & Rinehart, inc., 1940.