Sources: NElmC
- Samuel L. Clemens to Arthur Locker, 17 September 1872 · London, England · UCCL00808
- Samuel L. Clemens to John T. Lewis, 24 August 1877 · Elmira, N.Y. · 2nd of 2 · UCCL13815
- Samuel L. Clemens to Julia Jones Beecher, 30 May 1880 · Hartford, Conn · UCCL01809
- SLC to Unidentified, April 1883 · Hartford, Conn · UCCL11286
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