Sources: GMar2
- Samuel L. Clemens to James Redpath, 10 July 1871 (3rd of 3) · Elmira, N.Y · UCCL00636
- Samuel L. Clemens to Francis E. Bliss, 19 April 1872 · Elmira, N.Y · UCCL00741
- Samuel L. Clemens to Olivia L. Clemens, 7 August 1878 · Heidelberg, Germany · UCCL11926
- SLC to James R. Osgood, 21 January 1883 · Hartford, Conn · UCCL01632
- SLC to Henry M. Alden, 11 May 1891 · Hartford, Conn · UCCL04204
- SLC to Richard Watson Gilder, 17 June 1898 · Kaltenleutgeben, Austria · UCCL11927
- SLC to ? Osborne, 5 October 1901 · Riverdale, N.Y · UCCL11928
- SLC to Seaman, 18 January 1902 · Riverdale, N.Y · UCCL11929
- SLC to Adele D. Holt, 3 May 1907 · New York, N.Y · UCCL07712
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