Player, Mack A.
West Publishing, 1981
Buku Referensi
McDonald, Janis L.
Pearson/Prentice-Hall, 2006
Buku Teks
Willbrown, Steven L.
Michie Law, 1995
Buku Teks SO
Bennet-Alexander, Dawn
Irwin, McGraw-Hill, 2004
Buku Teks SO
edited by Roger Blanpain
Kluwer, 2008
Buku Teks SO