APA (7th ed.) Citation

Keen, M. L. (1974). The world beneath our feet: The story of soil. Messner.

Chicago Style (17th ed.) Citation

Keen, Martin L. The World Beneath Our Feet: The Story of Soil. New York: Messner, 1974.

MLA (9th ed.) Citation

Keen, Martin L. The World Beneath Our Feet: The Story of Soil. Messner, 1974.