Encyclopaedia Britannica, 1981
Buku Referensi
Encyclopaedia Britannica, 1981
Buku Referensi
Dickens, Charles, 1812-1870, author
Everyman`s Library, 1993
Buku Teks
Scott-Kilvert, Ian, author
Longmans, Green, 1970
Buku Teks
Brown, Arthur W., author
Twayne Publishers, 1964
Buku Teks