Tripp, Charles
Cambridge University Press, 2006
Buku Teks SO
Alekseyev, A.
Foreign Languages Publishing House, 1955
Buku Teks SO
Dalton, George
Penguin Education, 1975
Buku Teks SO
Epstein, T. Scarlett
Australian National University Press, 1968
Buku Teks SO
Potter, Jack M.
University California Press, 1968
Buku Teks SO