Graham, George A.
University of Alabama Press, 1960
Buku Teks
Braeman, John
Thomas Y Crowill, 1969
Buku Teks
Bailey, Stephen K., author
Henry Holt, 1957
Buku Teks
Moore, John A., author
Macmillan, 1985
Buku Teks
Chafe, William Henry
Oxford University Press, 1995
Buku Teks