APA (7th ed.) Citation

Doyle, A. C. (1975). A study in Scarlet and The sign of four (1a. ed.). Berkley Books.

Chicago Style (17th ed.) Citation

Doyle, Arthur Conan. A Study in Scarlet and The Sign of Four. 1a. ed. Nueva York: Berkley Books, 1975.

MLA (9th ed.) Citation

Doyle, Arthur Conan. A Study in Scarlet and The Sign of Four. 1a. ed. Berkley Books, 1975.