Casper, Lynne M., author
Sage, 2000
Buku Teks
Dyere, Everett D., author
McGraw-Hill, 1979
Buku Teks
Abramson, Paul R., author
A Division of Congressional Quarterly, 1986
Buku Teks
Cobb, Nancy J., author
Mayfield Publishing, 2000
Buku Teks
Cobb, Nancy J., author
Mayfield , 2001
Buku Teks