Timings, R.L. (Roger Leslie), 1927-, author
Longman, 1991
Buku Teks
H.K Rihan Int'l Culture Spread Limited, 2008
Buku Referensi
Bickley, Verner C., author
University of London Press, 1960
Buku Teks
Halliday, David, 1916-2010, author
John Wiley & Sons, 1994
Buku Teks
Beck, Christian, editor
Springer, 2012
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