Cox, Harold, author
Prentice-Hall, 1984
Buku Teks
Ferrini, Rebecca, author
McGraw-Hill, 2013
Buku Teks
Davies, Tom
Hodder & Stoughton, 1989
Buku Teks
Williams, David, author
Sweet & Makwell, 2000
Buku Teks
Davies, Robertson
Penguin Books, 1975
Buku Teks