Keene, C. (1981). The clue in the crossword cipher. Armada books.
Lua i Stíl Chicago (17ú heag.)Keene, Carolyn. The Clue in the Crossword Cipher. New York: Armada books, 1981.
Lua MLA (9ú heag.)Keene, Carolyn. The Clue in the Crossword Cipher. Armada books, 1981.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.