Goldsmith, Seth B.
Jones & Bartlett, 2011
Buku Teks
Healey, Bernard J.
Jossey- Bass, 2012
Buku Teks
edited by Stephen J. Williams
John Wiley & Sons, 1980
Buku Teks
Johnson, James A.
Delmar Cengage Learning, 2013
Buku Teks
Browdy, Jerad D.
An Aspen Publ., 1983
Buku Teks