Sources: MB
- Samuel L. Clemens to Elisha Bliss, Jr., 13 October 1870 · Buffalo, N.Y · UCCL00511
- Samuel L. Clemens to James Redpath, 15 May 1872 · Elmira, N.Y · UCCL00748
- Samuel L. Clemens to Kate Field, 9 June 1873 · London, England · UCCL00920
- Samuel L. Clemens to Chatto and Windus, 8 April 1874 · Hartford, Conn · UCCL01072
- Samuel L. Clemens to Charles Warren Stoddard, 1 February 1875 · Hartford, Conn · UCCL01187
- Samuel L. Clemens to Charles Warren Stoddard, 20 March 1878 · Hartford, Conn · UCCL01546
- SLC to Karl Gerhardt and Hattie J. Gerhardt, 9 May 1881 · Hartford, Conn · UCCL01952
- SLC to Karl Gerhardt, 30 May 1881 · Hartford, Conn · UCCL10064
- SLC to Karl and Hattie J. Gerhardt, 31 July 1881 · Branford, Conn · UCCL01991
- SLC to Karl Gerhardt and Hattie J. Gerhardt, 31 August 1881 · Elmira, N.Y · UCCL02019
- SLC to Karl Gerhardt and Hattie J. Gerhardt, 9 October 1881 · Hartford, Conn · UCCL02049
- SLC to Karl and Hattie J. Gerhardt, 7 November 1881 · Hartford, Conn · UCCL02083
- SLC to Karl Gerhardt and Hattie J. Gerhardt, 4 August 1882 · Elmira, N.Y · UCCL02259
- SLC to Karl Gerhardt and Hattie J. Gerhardt, 2 July 1883 · Elmira, N.Y · UCCL02300
- SLC to George Parsons Lathrop, 14 April 1884 · Hartford, Conn · UCCL02952
- SLC to Karl Gerhardt, 28 September 1884 · Hartford, Conn · UCCL01443
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