Robinson, Alan, author
Macmillan, 1988
Buku Teks
Koh, Chang-Soo, author
International Publishing House, 1987
Buku Teks
Gray, Richard, 1944-, author
John Wiley & Sons, 2015
Buku Teks
Gray, Richard, 1944-, author
Longman, 1991
Buku Teks
Bogan, Louise, author
Henry Regnery, 1951
Buku Teks