APA (7th ed.) Citation

Collins, A., & Doyle, A. C. (1992). The sign of four. Heinemann.

Chicago Style (17th ed.) Citation

Collins, Anne, and Arthur Conan Doyle. The Sign of Four. Oxford [etc.]: Heinemann, 1992.

MLA (9th ed.) Citation

Collins, Anne, and Arthur Conan Doyle. The Sign of Four. Heinemann, 1992.