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Cambridge university press , 2005
Buku Teks
Hinrichs, Roger A., author
Thomson, Brooks/Cole, 2006
Buku Teks
Warta IKAPI,
Majalah, Jurnal, Buletin
Moore, John Hammond, author
John Wiley & Sons, 1982
Buku Teks
Fowler, Robert Booth, author
Praeger, 1985
Buku Teks