Artikel Jurnal
Charles
Harvard University Press, 1973
Buku Teks
Editor by Ralph D. Casey
Louisiana State University, 1963
Buku Teks
Hayes, Nicky, author
Macmillan Press, 1995
Buku Teks
Ruzaimi Mat Rani, author
Words & Visuals Press Pte Ltd,
Buku Referensi