Kirn, Elaine
McGraw-Hill, 1990
Buku Teks SO
Allan, Dave
Oxford University Press, 1992
Buku Teks SO
Blair, Walter
Scott Foresman, 1955
Buku Teks SO
Funk & Wagnalls, 1980
Buku Referensi
Foreword by Wong Lian Aik
Center for English Language Communication. NUS, 2001
Buku Teks SO