APA (7th ed.) Citation

Gemmill, P. F., & Blodgett, R. H. (1948). Economics: Principles and problems (3rd ed.). Harper.

Chicago Style (17th ed.) Citation

Gemmill, Paul Fleming, and Ralph Hamilton Blodgett. Economics: Principles and Problems. 3rd ed. New York: Harper, 1948.

MLA (9th ed.) Citation

Gemmill, Paul Fleming, and Ralph Hamilton Blodgett. Economics: Principles and Problems. 3rd ed. Harper, 1948.