Shields, James J,Jr
Frederick A. Preager, 1967
Buku Teks
Redfield, Robert, author
The University of Chicago Press, 1962
Buku Teks
Sanders, Irwin T.
Ronald Press , 1966
Buku Teks
Brownell, Baker
Harper & Brothers Publishers , 1950
Buku Teks
Matthews, Mark Stanley.
Harper , 1954
Buku Teks