APA (7th ed.) Citation

Keene, C. (1971). The Clue In The Crossword Cipher.

Chicago Style (17th ed.) Citation

Keene, Carolyn. The Clue In The Crossword Cipher. London, 1971.

MLA (9th ed.) Citation

Keene, Carolyn. The Clue In The Crossword Cipher. 1971.

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