APA (7th ed.) Citation

Doyle, S. A. C. The sign of the four. s. n.

Chicago Style (17th ed.) Citation

Doyle, Sir Arthur Conan. The Sign of the Four. s. l: s. n.

MLA (9th ed.) Citation

Doyle, Sir Arthur Conan. The Sign of the Four. s. n.

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