Παραπομπή APA

Doyle, A. C. (1994). The Sign of the Four (1st.). OUP.

Παραπομπή Chicago Style

Doyle, Arthur Conan. The Sign of the Four. 1st. New York: OUP, 1994.

Παραπομπή MLA

Doyle, Arthur Conan. The Sign of the Four. 1st. OUP, 1994.