Clokie, H. Mcd.
Toronto Langmans, Green 1950
Buku Teks
University of Toronto Press, 2014
Buku Teks
Saywell, John J.
University of Toronto Press , 1957
Buku Teks
Buck, A. E., author
Public Administration Service, 1949
Buku Teks
Deutsch, Karl W
Houghton Mifflin, 1970
Buku Teks