Quigly, Isabel
The British Council and the National Book League by Longmans, 1968
Buku Teks
Butler, Rick
Doubleday & Company, Inc, 1978
Buku Teks
Butler, David
Radius Book/ Hutchinson, 1970
Buku Teks
Richie, Beth E
Routledge, 1996
Buku Teks
Betz, Nancy E.
Academic Press, 1987
Buku Teks