Karrass, Chester L.
Thomas Y. Crowell Company, 1970
Buku Teks
Fisher, Roger
Business Books, 2011
Buku Teks
Tan, Joo Seng
McGraw-Hill, 2004
Buku Teks
Mayberry, Grant E.
American Management Association, 1993
eBooks
Goodpaster, Gary
Elips Project, 1993
Buku Teks