Seng, Kenneth Wee Kim
University of Singapore, 1976
Buku Teks SO
Puxon, Margaret
Penguin Books, 1971
Buku Teks SO
Pace, P.J.
Pitman, 1992
Buku Teks SO
Menski, Werner F.
Curzon Press, 2001
Buku Teks SO
edited by Nochaya Talib, Siti Zaharah Jamaluddin and Jal Zabdi Mohd Yusof
university of Malaya Press, 2009
Buku Teks SO