APA (7th ed.) Citation

Keene. (1951). The clue of the black keys. Grosset and Dunlap.

Chicago Style (17th ed.) Citation

Keene. The Clue of the Black Keys. New York: Grosset and Dunlap, 1951.

MLA (8th ed.) Citation

Keene. The Clue of the Black Keys. Grosset and Dunlap, 1951.

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