Briggs, J. G. R.
Longman , 1998
Buku Teks
Tan, Yin Toon
Oxford University Press, 1995
Buku Teks
Meyers, Alan, 1945-, author
Pearson Education, 2014
Buku Teks
Fuchs, Philip L., author
Stipes, 1994
Buku Teks
Rasanayagam, L.J., author
Federal Publications, 1993
Buku Teks