Hughes, Charles W.
Columbia University Press, 1980
Buku Referensi
Pollard, Arthur
Longman, Green, 1960
Buku Teks
Simpson, David
Oxford University Press , 1986
Buku Teks
Gagey, Edmond M.
Columbia University Press, 1948
Buku Teks
Perosa, Sergio
New York University Press, 1985
Buku Teks