Allen, Judy, author
Wiley, 2003
Buku Teks
Brennan, Lynne, author
Platkus, 1991
Buku Teks
Allen, Judy, author
John Wiley & Sons Canada, Ltd., 2003
Buku Teks
Robinson, David
Gramedia Pustaka Utama, 1996
Buku Teks
Langford, Beverly Y., author
American Management Association, 2005
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