Mellor, John W., author
Cornell University Press, 1966
Buku Teks
edited by Melvin G. Blase
Iowa State University Press, 1971
Buku Teks
Report of a SEADAG Rural Development Seminar Meeting, 1969
Buku Teks
Norton, George W., author
McGraw-Hill, 1993
Buku Teks
Millikan, Max F., author
Little, Brown , 1967
Buku Teks