Bailey, Stephen K.
Henry Holt, 1957
Buku Teks
OConnor, Karen
Addison Wesley Longman, 2001
Buku Teks
Sayre, Wallace S.
Barnes & Noble, 1964
Buku Teks
Posey, Rollin Bennett
Littlefield, Adam, 1958
Buku Teks
Ferguson, John H.
McGraw-Hill, 1947
Buku Teks