Kay, Herma Hill, author
Harcourt Brace & Company, 1990
Buku Teks
Siegel, David D.
West Pub. Co., 1994
Buku Teks
Harmon, Sharon Koomen, author
John Wiley & Sons, 2001
Buku Referensi
Goodrich, Herbert F. (Herbert Funk), 1889-1962
West Publishing Company, 1927
Buku Teks
Scoles, Eugene F., author
West Publishing, 1992
Buku Teks