West, Anthony R.
John Wiley & Sons, 2014
Buku Teks
Elliott, Roger J.
English Language Book Society, 1978
Buku Teks
Thomason, Michael
Reston Publishing, 1979
Buku Referensi
Academic Press, 1984
Buku Teks
Goto, Kazuhiro Sylvester
Elsevier, 1988
Buku Teks