Jones, Manley Howe
Ill Irwin , 1957
Buku Teks
Bursk, Edward Collins, author
Cambridge, Mass, Harvard University Press
Buku Teks
Hindle, Tim, author
Harvard Business, 1993
Buku Referensi
Myers, M. Scott, author
McGraw-Hill, 1981
Buku Teks
Reis, Matthew, author
American Management Association, 2010
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