Campbell-Johnson, Alan, author
Ives Washburn, 1955
Buku Teks
Routledge, 2000
Buku Teks
Taylor, Henry
New York A Mentore Books New American Library 1958,
Buku Teks
MacMillan St Martin's Press, 1953
Buku Referensi
Uldrich, Jack, author
[American Management Association, ], 2005
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