Keene, C. (1981). The clue in the crossword cipher. Armada books.
Chicago Style (17th ed.) ZitazioaKeene, Carolyn. The Clue in the Crossword Cipher. New York: Armada books, 1981.
MLA (9th ed.) ZitazioaKeene, Carolyn. The Clue in the Crossword Cipher. Armada books, 1981.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.