Robinson, Derek
Churchill Livingstone, 1985
Buku Teks
Zhdanov, V., author
Foreign Languages Publishing House, [date of publication not identified]
Buku Teks
Susser, Mervyn
Oxford University Press, 1973
Buku Teks
Peterson, Donald R.
Massachusetts Lexington Books, 1978
Buku Teks
Fox, John P., author
Macmillan, 1970
Buku Teks