Bowers, Helen, author
Firefly Books, 2004
Buku Teks
Knackstedt, Mary V., author
Wiley, 2005
Buku Referensi
Midgley, Barry, editor
Chartwell Books, 1982.
Buku Referensi
Edited by Angela Gair
Chronicle Books, 1996
Buku Referensi
Godsey, Lisa, author
Fairchild Books, 2010
Buku Teks