Research articles (which your professor may also call peer-reviewed, refereed, or academic articles) are considered the most reliable information sources. They are written by experts and go through a rigorous process where other subject experts analyze and critique the arguments to identify errors, faulty logic, and other problems.
News Articles are usually considered primary sources and are excellent for finding information about an event around the time that it occurred. They are not peer-reviewed or scholarly in nature.
Legal Research involves finding the legislation, court cases, and law review discussions that make up the American judicial system.
Demographics and Statistics links you to statistical information sites.
Richmond Resources are site for local information.