Ripley, Randall B.
The Dorsey Press, 1980
Buku Teks
The National Council on Public Works Improvement , 1988
Buku Teks
Franck, Thomas M.
Oxford University Press, 1979
Buku Teks SO
Kennedy, John F. (John Fitzgerald), 1917-1963
Harper & Brother, 1962
Buku Teks SO
CBO, 1988
Buku Teks