http://www.presidency.ucsb.edu/
John Woolley and Gerhard Peters, Department of Political Science, University of California at Santa Barbara
Types of Materials: Document sets, audio, video, data, and links
The site contains historical information and data relating to Presidential elections, national political parties, Presidential popularity, growth of the executive branch, and relations with Congress. The site also makes available primary source materials, including the Public Papers of the President and Presidential Inaugural Addresses, as well as audiovisual material, such as the television broadcast of Nixon's resignation announcement and audio of his address to the nation announcing the conclusion of an agreement ending the Vietnam War.