Shermen, Stanley N.
Wordcrafters Publications, 1991
Buku Teks
Bailey, Stephen K., author
Henry Holt, 1957
Buku Teks
OConnor, Karen, author
Addison Wesley Longman, 2001
Buku Teks
Sayre, Wallace S., author
Barnes & Noble, 1964
Buku Teks
Posey, Rollin Bennett, author
Littlefield, Adam, 1958
Buku Teks