Hart, James, author
The Johns Hopkins Press, 1930
Buku Teks
edited by Leonard D. White
University of Chicago Press, 1945
Buku Teks
Liff, Stewart, author
American Management Association;, 2010
eBooks
Bernard, Hugh Y.
Oceania Publications, Inc., 1968
Buku Teks
Nowak, John E., author
Thomson/West, 2010
Buku Teks