Smith, Walter Denton
West Publishing, 1939
Buku Teks
UTZ, Peter, author
Prentice-Hall, 1982
Buku Teks
Cox, D. R. (David Roxbee)
Methuen , 1963
Buku Teks
by Tan Cheng Han... [et.al.]
Sweet & Maxwell Asia, 2005
Buku Teks
Smith, J. C. (James Cruickshanks), 1867-1946, author
English Language Book Society, 1988
Buku Teks