Berenson, Mark L., author
Prentice-Hall, 1993
Buku Teks
Anderson, David R., author
West Publishing, 1981
Buku Teks
Daniel, Wayne W., author
Houghton Miffiln, 1989
Buku Teks
Michael S. Lewis-Beck, editor
Sage Publications, 1993
Buku Referensi
Becker, William E., author
Addison-Wesley, 1987
Buku Teks