Raven, Bertram H.
John Wiley & Sons, 1983
Buku Teks SO
Taylor, Shelley E.
Prentice-Hall, 1997
Buku Teks
Baron, Robert A.
Allyn and Bacon , 1997
Buku Teks
Myers, David G.
McGraw-Hill, 2005
Buku Teks
Taylor, Shelley E.
Pearson-Prentice Hall, 2006
Buku Teks