Lamb, George P.
Little, Brown, 1971
Buku Teks
Lamb, George P.
Little,Brown and Company, 1971
Buku Teks
D`arcy, Leo, author
Sweet and Maxwell, 2000
Buku Teks
Davidson, George
Hodder and stoughton, 1989
Buku Teks
Schmitthoff, Clive M., author
Stevens and Sons Limited, 1975
Buku Teks