O`Donnell, Mike, author
Longman, 1991
Buku Teks
Jae, Ho-chung, author
Columbia University Press, 2006
Buku Teks
Stout, Hiram Miller, author
Oxford University Press, 1953
Buku Teks
Williams, Basil, author
Oxford University, 1945
Buku Klasik
Dalton, Heather, author
Oxford University Press, 2016
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