Nicholson, John, author
BBC Books , 1992
Buku Teks
Mather, Hal, author
McGraw-Hill, 1984
Buku Teks
Pickering, Peg, author
Erlangga, 2001
Buku Teks
Humphries, john
Groiler International, 1993
Buku Teks
Chan, Janis Fisher, author
[American Management Association;, ], 2007
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