Kroeker, Irvin
Whitecap Books, 1979
Buku Teks SO
Morton, W.L.
University of Toronto Press, 1979
Buku Teks SO
Sweezy, Paul M. (Paul Marlor), 1910-2004
McGraw-Hill, 1949
Buku Teks SO
Sweezy, Paul M. (Paul Marlor), 1910-2004
McGraw-Hill, 1949
Buku Teks SO
Banfield, Edward C.
Free Press, 1951
Buku Teks SO