APA (7th ed.) Citation

Mills, E. A., & Schmeckebier, L. F. (1917). Your national parks. Houghton Mifflin Company.

Chicago Style (17th ed.) Citation

Mills, Enos A., and Laurence F. Schmeckebier. Your National Parks. Boston, New York: Houghton Mifflin Company, 1917.

MLA (9th ed.) Citation

Mills, Enos A., and Laurence F. Schmeckebier. Your National Parks. Houghton Mifflin Company, 1917.