R.A. Hope, J.M. Longmore, T.J. Hodgetts, P.S. Ramrakha
Oxford University Press, 1993
Buku Teks SO
Collier, J.A.B
Oxford University Press, 1995
Buku Teks SO
Collier, J.A.B
Oxford University Press, 1995
Buku Teks SO
Murray Longmore [and others]
Oxford University press, 2014
Buku Teks
Spickett, Gavin
Oxford University Press, 1999
Buku Referensi