Bajpai, Avi C.
John Wiley & Sons, 1983
Buku Teks SO
Slavin, Steve
John Wiley & Sons, 2007
Buku Teks SO
Dalven, Richard
The McGraw-Hill, 1998
Buku Teks SO
Frey, Alexander H.
Enslow Publishers, 1982
Buku Referensi
Kennamer, Mike
Thomson/Delmar Learning, 2005
Buku Teks SO