1Thomas Jefferson to Peter S. Du Ponceau, 14 March [1819] (Jefferson Papers)
American Philosophical Society, Historical and Literary Committee; Transactions [index entry]
2Peter S. Du Ponceau to Thomas Jefferson, 1 March 1819 (Jefferson Papers)
American Philosophical Society, Historical and Literary Committee; Transactions [index entry]
3Frederick A. Mayo to Thomas Jefferson, 30 March 1819 (Jefferson Papers)
American Philosophical Society, Historical and Literary Committee; Transactions [index entry]
4Thomas Jefferson to Frederick A. Mayo, 25 March 1819 (Jefferson Papers)
American Philosophical Society, Historical and Literary Committee; Transactions [index entry]