Boyer, Ralph E., author
St. Paul Minn, 1991
Buku Teks
Robin, R.H. (Robert Henry), author
Longman, 1980
Buku Teks
Bube, Richard H., author
Academic Press, 1981
Buku Teks
Waddams, A. Lawrence
The English Language Boook Society and John Murray, , 1968"
Buku Teks
Gray, Alexander, author
Longmans , 1959
Buku Teks