Doyle, Arthur Conan (1859-1930). (ang.) Sign of four ( w 1 rekordach )
- Doyle, Arthur Conan
- Kp. The adventures of Sherlock Holmes ; The memoirs of Sherlock Holmes ; The return of Sherlock Holmes ; Astudy in scarlet ; The sign of four ; The hound of the Baskervilles / Arthur Conan Doyle. - 4th impr. - London, 1982.
- LCA online