Drake, Henry Burgess
Oxford University, 1957
Buku Teks
Wilson, John B.
Longmans Green , 1958
Buku Teks
Lerner, Laurence D.
Oxford University Press, 1954
Buku Teks
Eaglestone, Robert
Routledge , 2005
Buku Teks
Baker, Nancy L.
The Modern Language Association of america, 1985
Buku Referensi