Addressees: Twichell, Harmony C
- Samuel L. Clemens to Joseph H. and Harmony C. Twichell, 18 November 1868 · Cleveland, Ohio · UCCL02765 CtY-BR
- Samuel L. Clemens to Joseph H. and Harmony C. Twichell, 12 November 1870 · Buffalo, N.Y · UCCL00533 CtY-BR
- Samuel L. Clemens to Joseph H. and Harmony C. Twichell, 19–22 March 1872 · Elmira, N.Y · UCCL00735 PBL
- Samuel L. Clemens to Joseph H. and Harmony C. Twichell, 11 June 1874 · Elmira, N.Y · UCCL01097 CtY-BR
- SLC to Joseph H. Twichell and Harmony C. Twichell, 24 December 1885 · Hartford, Conn · UCCL03342 CtY
- SLC to Joseph H. Twichell and Harmony C. Twichell, 27 December 1909 · Redding, Conn · UCCL08525 CtY-BR
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