Eastop, T.D. (Thomas D.)
Wiley, 1994
Buku Teks
Balzhiser, Richard E.
Prentice Hall of India, 1977
Buku Teks
Haberman, William L., 1922-
Boston: Allyn and Bacon, 1980
Buku Teks
Myers, Glen E.
Prentice-Hall, 1989
Buku Teks
Haberman, William L., 1922-
Allyn and Bacon, 1980
Buku Teks