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Universitas Brawijaya, 2005
Buku Teks
Wallwork, Adrian, author
Springer, 2010
Buku Teks
Dignen, Bob
York Associates, 1999
Buku Teks
Sweeney, Simon, author
Cambridge university press, 2010
Buku Teks
Hunter, Lynne, author
Prentice Hall Regents, 1989
Buku Teks