1Nicolas G. Dufief to Thomas Jefferson, 7 January 1817 (Jefferson Papers)
Enfield, William; The History of Philosophy [index entry]
2Nicolas G. Dufief to Thomas Jefferson, 30 January 1817 (Jefferson Papers)
Enfield, William; The History of Philosophy [index entry]
3Nicolas G. Dufief to Thomas Jefferson, 30 January 1817 (Jefferson Papers)
Enfield, William; The History of Philosophy [index entry]
4John Laval to Thomas Jefferson, 25 April 1817 (Jefferson Papers)
Enfield, William; The History of Philosophy [index entry]