Strother, Edgar E.
North-China Daily News and Herald , 1927
Buku Teks
Korner, S., author
Penguin Books, 1955
Buku Teks
Mehta, Pavithra K., author
Berrett Koehler, 2011
Buku Teks
Thomas, G. A. (Graham A.), author
John Blake, 2011
Buku Teks
Cohen, William A., author
American Management Association, 2008
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