Iacobucci, Dawn
John Wiley , 2001
Buku Teks
Reedy, Joel, author
The Dryden Press, 2000
Buku Teks
Brannan, Tom, author
Crest Publishing House, 2001
Buku Teks
edited by Reavis Cox and Wroe Alderson
Richard D. Irwin, 1950
Buku Teks
Douglas, Edna
Harper & Row , 1975
Buku Teks