Green, D.C., author
Longman, 1988
Buku Teks
Horowitz, Paul, author
Cambridge University Press, 1980.
Buku Teks
Green, D.C., author
Longman, 1995
Buku Teks
Romanowitz, H. Alex, author
John Wiley & Sons, 1968
Buku Teks
Horowitz, Paul, author
Cambridge University Press, 1980
Buku Teks