Doyle, A. C., & Page, J. (2010). Sherlock Holmes: The sign of four. Oxford University Press.
Lua i Stíl Chicago (17ú heag.)Doyle, Arthur Conan, agus Jeremy Page. Sherlock Holmes: The Sign of Four. Oxford: Oxford University Press, 2010.
Lua MLA (8ú heag.)Doyle, Arthur Conan, agus Jeremy Page. Sherlock Holmes: The Sign of Four. Oxford University Press, 2010.
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