Batra, Ravi
Simon and Schuster , 1988
Buku Teks
Williams, Venus, author
Amistad, 2010
Buku Teks
Robbins, Lionel Robbins, Baron, 1898-1984, editor
Macmilan Co., 1936
Buku Teks
Hayes, Kenney, author
Gramedia Pustaka Utama, 2004
Buku Teks
Straub, Joseph T., author
American Management Association, 2000
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