Popovich, Igor S., author
Abdi Tandur, 1996
Buku Teks
McGraw-Hill/Glencoe, 2003
Buku Teks
Bostwick, Burdette E., author
John Wiley & Sons, 1981
Buku Teks
Fry, Ron, author
Career Press, 2002
Buku Teks
Nierenberg, Alan H., author
American Management Association, 2005
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