Cita APA (7a ed.)

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

Cita Chicago Style (17a ed.)

Doyle, Arthur Conan sir, y Anne Collins. The Sign of Four. Oxford: Heinemann, 1992.

Cita MLA (8a ed.)

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