1Horatio G. Spafford to Thomas Jefferson, 24 February 1815 (Jefferson Papers)
Williams, Samuel (1743–1817); The Natural and Civil History of Vermont [index entry]
2Horatio G. Spafford to Thomas Jefferson, 28 February 1822 (Jefferson Papers)
Williams, Samuel (1743–1817); The Natural and Civil History of Vermont [index entry]
3Horatio G. Spafford to Thomas Jefferson, 6 April 1815 (Jefferson Papers)
Williams, Samuel (1743–1817); The Natural and Civil History of Vermont [index entry]