edited by George M. Foster and Robert V. Kemper
Little, Brown, 1974
Buku Teks
Barnett, Jonathan, author
Planners Press, 2003
Buku Teks
Law, Christopher M., author
Continuum, 2002
Buku Teks
Orum, Anthony M., author
Blackwell, 2003
Buku Teks
Maier, Henry W
Random House, 1966
Buku Teks