1Thomas Jefferson to John Barnes, 31 December 1816 (Jefferson Papers)
A Treatise on Political Economy (Destutt de Tracy) [index entry]
2Thomas Jefferson to John Barnes, 12 October 1816 (Jefferson Papers)
A Treatise on Political Economy (Destutt de Tracy) [index entry]
3Enclosure: Joseph Milligan to John Barnes, 21 October 1816 (Jefferson Papers)
A Treatise on Political Economy (Destutt de Tracy) [index entry]
4Thomas Jefferson to John Barnes, 17 May 1817 (Jefferson Papers)
A Treatise on Political Economy (Destutt de Tracy) [index entry]