Journals, diaries, and autobiographies are primary documents.
The Public Papers of the Presidents is a series starting with Herbert Hoover and continuing through Barak Obama that contains messages to Congress, speeches, transcripts of news conferences, selected important press releases of the White House and other activities of the Presidents (read more information about the series). The print series is in the Government Documents Collection on the ground floor of the JB Duke Library. The online version of The Public Papers of the Presidents is available for Presidents Reagan through Obama.
For earlier Presidents see:
Papers of John Adams (print)
The Papers of Andrew Jackson (print)
The Correspondence of James Polk (print)
The Papers of Andrew Johnson (print)
The Papers of Ulysses S. Grant (print)
The Works of Theodore Roosevelt (print)
The Papers of Woodrow Wilson (print)