APA (7th ed.) Citation

Doyle, A. C. (1994). The sign of the four. Oxford University Press.

Chicago Style (17th ed.) Citation

Doyle, Arthur Conan. The Sign of the Four. Oxford [England]: Oxford University Press, 1994.

MLA (9th ed.) Citation

Doyle, Arthur Conan. The Sign of the Four. Oxford University Press, 1994.