Davenport, Dawn, author
Broadway Books, 2006
Buku Teks
Porter, Lindsay, author
Porter Publishing, 1995
Buku Referensi
Jackson, Paul, author
Chancellor, 1994
Buku Referensi
Griffith, H. Winter, author
Fisher Books, 1998
Buku Teks
Baker, Sunny, author
Prentice-Hall, 1992
Buku Referensi