11John Laval to Thomas Jefferson, 25 April 1817 (Jefferson Papers)
Enfield, William; The History of Philosophy [index entry]
12Thomas Jefferson to Thomas Cooper, 14 August 1820 (Jefferson Papers)
Enfield, William; The History of Philosophy [index entry]
13Thomas Jefferson to John Adams, 15 August 1820 (Jefferson Papers)
Enfield, William; The History of Philosophy [index entry]