Sue, DAvid
Houghton Mifflin, 1986
Buku Teks
Tortoriello, Thomas R.
MaGraw-Hill , 1978
Buku Teks
Holme, David J., author
Longman Scientific & Technical, 1993
Buku Teks
Prentice-Hall, 1980
Buku Teks
Williams, David J., author
Prentice - Hall , 1971
Buku Teks