Buku Teks
Mennes, L.B.M.
North-Holland Publishing, 1969
Buku Teks
Adelman, Irma
Stanford University Press, 1961
Buku Teks
Hirschman, Albert O., editor
New York, N.Y. University Press, 1958
Buku Teks
edited by Richard N. Gardner and Max F. Millikan
Praeger , 1968
Buku Teks