McDonald, Janis L., author
Pearson/Prentice Hall, 2006
Buku Teks
Bennet-Alexander, Dawn, author
Irwin/McGraw-Hill, 2004
Buku Teks
Player, Mack A., author
West Publishing, 1981
Buku Referensi
London Pitman Pub. 1992,
Buku Teks
Pitman Pub., 1992
Buku Teks