Morrow, Vincent
Prentice-Hall, 1991
Buku Referensi
Gup, Benton E.
Richard D. Irwin, 1996
Buku Referensi
editor, Brian J. Terry
Toppan Company, 1997
Buku Referensi
edited by Mike Wright, Donald S. Siegel, Kevin Keasey and Igor Filatotchev
Oxford University Press, 2014
Buku Referensi
Emery, Douglas R.
Prentice-Hall, 1997
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