APA (7th ed.) Citation

Keene, C. (1935). The message in the hollow oak. Grosset & Dunlap.

Chicago Style (17th ed.) Citation

Keene, Carolyn. The Message in the Hollow Oak. New York: Grosset & Dunlap, 1935.

MLA (9th ed.) Citation

Keene, Carolyn. The Message in the Hollow Oak. Grosset & Dunlap, 1935.