Cassady, Marshall, author
National Textbook, 1993
Buku Teks
New York : Science Press
Majalah, Jurnal, Buletin
Elam, Keir, author
Methuen, 1980
Buku Teks
Arnold, Stephanie, author
Mayfield Publishing Company, 2001
Buku Teks
Bowers, Faubion, author
Thomas Nelson & Sons, 1956
Buku Teks