1José Corrêa da Serra to Thomas Jefferson, 11 October 1820 (Jefferson Papers)
Vanuxem, Lardner Clark; and T. Cooper [index entry]
2John Vaughan to Thomas Jefferson, 11 October 1820 (Jefferson Papers)
Vanuxem, Lardner Clark; and T. Cooper [index entry]
3Peter S. Du Ponceau to Thomas Jefferson, 23 March 1821 (Jefferson Papers)
Vanuxem, Lardner Clark; and T. Cooper [index entry]
4Thomas Jefferson to Peter S. Du Ponceau, 31 March 1821 (Jefferson Papers)
Vanuxem, Lardner Clark; and T. Cooper [index entry]