Sloman, John
Harvester Wheatsheaf, 1994
Buku Teks
Lipsey, Richard G.
Harper Collin, 1996
Buku Teks
Albrecht, William P.
Prentice-Hall, 1979
Buku Teks
Adreson, W. H. Locke
Prentice Hall of India, 1986
Buku Teks
Bowden, Elbert V.
Alexander Hamilton Institute , 1962
Buku Teks