APA (7th ed.) Citation

Bolton, H. E. (1939). Wider horizons of America history. D. Appleton-Century.

Chicago Style (17th ed.) Citation

Bolton, Herbert Eugene. Wider Horizons of America History. New York: D. Appleton-Century, 1939.

MLA (9th ed.) Citation

Bolton, Herbert Eugene. Wider Horizons of America History. D. Appleton-Century, 1939.