Blackman, Carolyn
Allen & Unwin, 1997
Buku Teks
Karrass, Chester L.
Thomas Y. Crowell Company, 1970
Buku Teks
Fisher, Roger, author
Business Books, 2011
Buku Teks
Mayberry, Grant E., author
American Management Association, 1993
eBooks
Tan, Joo Seng, author
McGraw-Hill, 2004
Buku Teks