Evans, Michael
Butterworth, 1993
Buku Teks
Pettit, Philip H.
English Language Book Society , 1985
Buku Teks
Todd, Paul
London Blackstone 1996.,
Buku Referensi
Keeton, George W., 1902-1989, author
Sir Isaac Pitman and Sons, 1950
Buku Teks
Heydon, J.D.
Butterworth, 1993
Buku Teks