1Thomas Jefferson to Horatio G. Spafford, 26 April 1814 (Jefferson Papers)
Spafford, Horatio Gates; inventions of [index entry]
2Thomas Jefferson to Horatio G. Spafford, 21 February 1815 (Jefferson Papers)
Spafford, Horatio Gates; inventions of [index entry]
3Thomas Jefferson to Horatio G. Spafford, 15 March 1815 (Jefferson Papers)
Spafford, Horatio Gates; inventions of [index entry]
4Thomas Jefferson to Horatio G. Spafford, 14 May 1815 (Jefferson Papers)
Spafford, Horatio Gates; inventions of [index entry]