APA (7th ed.) Citation

Knowlton, H. (1941). Air transportation in the United States: Its growth as a business. The University of Chicago press.

Chicago Style (17th ed.) Citation

Knowlton, Hugh. Air Transportation in the United States: Its Growth as a Business. Chicago, Ill.: The University of Chicago press, 1941.

MLA (9th ed.) Citation

Knowlton, Hugh. Air Transportation in the United States: Its Growth as a Business. The University of Chicago press, 1941.