Simon and Schuster, 1968
Buku Teks
Booth, Tim, author
Routledge, 1998
Buku Teks
Rothenberg, Robert E, author
The Danbury Press, 1976
Buku Teks
Shucksmith, Janet, author
Routledge, 1998
Buku Teks
Sweet, Fay, author
Conran Octopus Limited, 2000
Buku Referensi