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Majalah, Jurnal, Buletin
editor, Cynthia Macdonald and Garaham Macdonald
Blackwell Publishers, Ltd., 1995
Buku Teks
Kusch, Martin, author
Routledge, 1999
Buku Teks
Hauser, Arnold, author
Routledge & Kegan Paul, 1959
Buku Teks
Derry, Jan, author
Wiley-Blackwell, 2013
Buku Teks