APA (7th ed.) Citation

Ennis, W. D. (1911). Flying machines to day. D. Van Nostrand.

Chicago Style (17th ed.) Citation

Ennis, William Duane. Flying Machines to Day. New York: D. Van Nostrand, 1911.

MLA (9th ed.) Citation

Ennis, William Duane. Flying Machines to Day. D. Van Nostrand, 1911.