Webster, Frank
Routledge, 2014
Buku Teks SO
Webster, Frank
Routledge, 1995
Buku Teks SO
Currie, Wendy
John Wiley & Sons, 2000
Buku Teks SO
Abrizah Abdullah... (et al.)
University of Malaya, 2007
Buku Teks SO
Al-Hawamdeh, Suliman
McGrawHill, 2002
Buku Teks SO