1Peter S. Du Ponceau to Thomas Jefferson, 5 December 1817 (Jefferson Papers)
Biddle, Nicholas; and American Philosophical Society [index entry]
2Peter S. Du Ponceau to Thomas Jefferson, 6 January 1818 (Jefferson Papers)
Biddle, Nicholas; and American Philosophical Society [index entry]
3John Vaughan to Thomas Jefferson, 12 February 1818 (Jefferson Papers)
Biddle, Nicholas; and American Philosophical Society [index entry]
4Enclosure: Nicholas Biddle to William Tilghman, 6 April 1818 (Jefferson Papers)
Biddle, Nicholas; and American Philosophical Society [index entry]
5Peter S. Du Ponceau to Thomas Jefferson, 14 April 1818 (Jefferson Papers)
Biddle, Nicholas; and American Philosophical Society [index entry]