Tripp, Charles
Cambridge University Press, 2006
Buku Teks
Alekseyev, A.
Foreign Languages Publishing House, 1955
Buku Teks
Dalton, George
Penguin Education, 1975
Buku Teks
Barish, Norman N.
McGraw-Hill, 1987
Buku Teks
Keat, Paul G.
Pearson Education (Prentice Hall), 2009
Buku Teks