Ritter, Peck
Brooks/Cole Publishing, 1996
Buku Teks SO
Anderson, Arthur K.
John Wiley & Sons, 1953
Buku Teks SO
Harper, Harold A.
EGC, 1977
Buku Teks
Holum, John R.
John Wiley & Sons, 1975
Buku Teks SO
Rao, K. Ranganatha
Prentice Hall of India, 1980
Buku Teks SO