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Buku Referensi
Bloomsbury , 2002
Buku Referensi
Monger, Rod F., author
The Free Press, 1988
Buku Teks
Mike Millmore, Philip Lewis, Mark Saunders, Adrian Thornhill, Trevor Morrow
Prentice-Hall, 2007
Buku Teks
Stone, Raymond J., author
John Wiley & Sons, 1995
Buku Teks