Sources: OFH
- Samuel L. Clemens to William Dean Howells, 27 February 1874 · Hartford, Conn · UCCL01058
- Samuel L. Clemens to Charles Warren Stoddard, 20 September 1876 · Hartford, Conn · UCCL01366
- Samuel L. Clemens to William Dean Howells, 22 February 1877 · Hartford, Conn · UCCL01533
- Samuel L. Clemens to George W. McCrary, 27 February 1877 · Hartford, Conn · UCCL09190
- SLC to Lucy Webb Hayes, 24 January 1881 · Hartford, Conn · UCCL09312
- SLC to Rutherford B. Hayes, 10 April 1882 · Hartford, Conn · UCCL02198
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