McArthur, Tom (Thomas Burns), author
Cambridge University Press, 1983
Buku Teks
Artikel Jurnal
Baker, Colin, author
Multilingual Matters Ltd., 1995
Buku Referensi
Artikel Jurnal
Phares Odaffer, Randall Charles, Thomas Cooney, John Dossey, Jane Schielack
Pearson Addison Wesley, 2008
Buku Teks