1Thomas Jefferson to Meriwether Lewis, 16 August 1809 (Jefferson Papers)
2Benjamin Smith Barton to Thomas Jefferson, 16 October 1810 (Jefferson Papers)
3Thomas Jefferson to Benjamin Smith Barton, 22 October 1810 (Jefferson Papers)
4Benjamin Smith Barton to Thomas Jefferson, 1 May 1811 (Jefferson Papers)
5Thomas Jefferson to Joseph C. Cabell, 13 July 1816 (Jefferson Papers)