Woodward, Ralph Lee, author
Oxford University Press , 1985
Buku Referensi
Booth, John A., author
Westerview Press, 1989
Buku Teks
Campbell, John C., author
Harper & Row, 1967
Buku Teks
Dulles, Foster Rhea, author
Princeton University Press, 1944
Buku Teks
edited by Louis W. Goodman, William M. LeoGrande, Johanna Mendelson Forman
Westview Press, 1992
Buku Teks