Rubin, Seymour J.
Harper & Row, 1966
Buku Teks
Bruton, Henry J
Prentice-Hall, 1965
Buku Teks
Bryce, Murray D.
The McGraw-Hill Book Company, 1960
Buku Teks
Adelman, Irma
Stanfor University Press , 1961
Buku Teks
Hirschman, Albert O., editor
New York, N.Y. University Press, 1958
Buku Teks