Hedgecoe, John
Ebury, 1992
Buku Referensi
Feininger, Andreas
Englewood Cliffs, 1969
Buku Teks
Bowen, Christopher J.
Focal Press, 2013
Buku Teks
Miller, Peter
Little, Brown and Company, 1983
Buku Teks
Sinclair, Joseph T.
American Management Association, 2005
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