1Thomas Jefferson to John Adams, 14 October 1816 (Jefferson Papers)
2Thomas Jefferson to John Adams, 25 November 1816 (Jefferson Papers)
3Thomas Jefferson to Destutt de Tracy, 15 May 1817 (Jefferson Papers)
4Thomas Jefferson to Robert Walsh, 9 January 1818 (Jefferson Papers)
5Thomas Jefferson to Robert Walsh, 19 February 1818 (Jefferson Papers)
6Thomas Jefferson to Destutt de Tracy, 26 December 1820 (Jefferson Papers)
7Thomas Jefferson to Francis Eppes, 27 June 1821 (Jefferson Papers)