Swales, John M., author
The University of Michigan Press, 2004
Buku Teks
Meyers, Alan, 1945-, author
Pearson Education, 2014
Buku Teks
David Alistair Watts, author
Artikel Jurnal
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Cambridge , 1999
Buku Referensi
Belcher, Wendy Laura, author
Sage Publications, 2009
Buku Teks