Dillingham, Alan E.
Allyn and Bacon , 1992
Buku Teks
Becker, William E., author
Prentice-Hall, 1971
Buku Teks
Atkinson, Lloyd C., author
Richard D. Irwin, 1982
Buku Teks
Gwartney, James D., author
The Reyden Press, 2000
Buku Teks
Gwartney, James D.
FL. The Dryden Press, 1995
Buku Teks