Greenberg, Jerald
Prentice-Hall, 2000
Buku Teks
Engel, James F.
The Dryden Press , 1995
Buku Teks
Schermerhorn, John R.
John Wiley & Sons, 2003
Buku Teks
Wells, William D.
John Wiley & Sons, 1996
Buku Teks
Schiffman, Leon G.
Pearson Education International, 2004
Buku Teks