Davies, liz, author
Learning Matters Ltd., 2008
Buku Teks
Elias, Maurice J., author
Kaifa , 2003
Buku Teks
Papalia, Diane E.
McGraw-Hill, 2006
Multimedia
Wilmshurst, Linda, author
New Jersey, 2005
Buku Teks
Jersild, Arthur T., author
Prentice-Hall, 1968
Buku Teks