Fisher, David T.
Prentice-Hall, 1991
Buku Referensi
Andrews, jean
Course technology cengage learning, 2013
Buku Teks SO
Andrews, jean
Course Technology, 2013
Buku Teks SO
Ayres, James J.
New York: John Wiley & Sons, 1990,
Buku Referensi
Keet, Ernest E.
Addison-Wesley, 1984
Buku Teks SO