McMullin, Rian E, author
W.W. Norton, 2000
Buku Teks
Westring, Gosta B.
N.Y. United Nations Institute for traning and research , 1974
Buku Teks
Institute of Management and Administration (IOMA)
John Wiley & Sons, 2006
Buku Teks
Bowles, Joseph E., author
McGraw-Hill, 1980
Buku Referensi
Hanford, James Holly
F.S. Croff & Co., 1946
Buku Teks