APA (7th ed.) Citation

Gemmill, P. F. (1931). An economics question book: Questions and problem for introductiory college courses in economic principles. Harper & brothers.

Chicago Style (17th ed.) Citation

Gemmill, Paul F. An Economics Question Book: Questions and Problem for Introductiory College Courses in Economic Principles. New York, London: Harper & brothers, 1931.

MLA (9th ed.) Citation

Gemmill, Paul F. An Economics Question Book: Questions and Problem for Introductiory College Courses in Economic Principles. Harper & brothers, 1931.