Pechenik, Jan A., author
Longman , 2001
Buku Teks
Pechenik, Jan A., author
Pearson Longman, 2007
Buku Teks
Dunn, Dana S., author
Longman, 2011
Buku Teks
Clymo, R. S, author.
Cambridge University Press, 2014.
Buku Teks
Barnet, Sylvan, author
Batsford Academic and Educational, 1985
Buku Teks