Clark, James E., author
Houghton Mifflin, 2002
Buku Teks
Heilbroner, Robert L., author
Prentice-Hall, 1972
Buku Teks
Rowan, D.C., author
Macmillan, 1968
Buku Teks
Rowan, D.C., author
Macmillan, 1978
Buku Teks
Darby, Michael R.
McGraw-Hill, 1976
Buku Teks