Rosati, Jerel A., 1953-, author
Thomson, 2004
Buku Teks
Knauth, Oliver D.
Nasional Planning Association, 1960
Buku Teks
Cohen, Bernard Cecil, 1926-, author
Princeton University Press, 1969
Buku Teks
Magdoff, Harry, author
Modern Reader Paperbacks, 1969
Buku Teks
Molineu, Harold, author
Westerview Press, 1990
Buku Teks