APA (7th ed.) Citation

Barkley, F. A. (1967). Outline classification of organisms. Hopkins Press.

Chicago Style (17th ed.) Citation

Barkley, Fred A. Outline Classification of Organisms. Providence: Hopkins Press, 1967.

MLA (9th ed.) Citation

Barkley, Fred A. Outline Classification of Organisms. Hopkins Press, 1967.

Warning: These citations may not always be 100% accurate.