McKenna, John R.
Harper and Row , 1971
Buku Teks
Hoag, Erleen J.
Prentice-Hall, 1991
Buku Teks
Kohler, Heinz, author
Alfred A. Knoff , 1961
Buku Teks
edited by Paul A. Samuelson
McGraw-Hill, 1970
Buku Teks
Hailstones, Thomas J., author
South-Western Publishing, 1974
Buku Teks