Sources: CtHSD
- SLC to Isabella Beecher Hooker, 24 January 1868 · Hartford, Conn · UCCL13620
- Samuel L. Clemens to Hattie Booth, 18 March 1870 · Buffalo, N.Y · UCCL00445
- Samuel L. Clemens to Jesse C. Haney, 14 November 1870 · Buffalo, N.Y · UCCL00534
- Olivia L. and Samuel L. Clemens to Alice Hooker Day, 25 January 1871 · Buffalo, N.Y · UCCL00564
- Samuel L. Clemens to Mary Mason Fairbanks, 6 November–10 December 1872 · London, England, or Hartford, Conn · UCCL11817
- Samuel L. Clemens to Henry Lee, 12 and 13 June 1873 · London, England · UCCL00924
- Samuel L. Clemens to Edward T. Potter, 8 May 1874 · Elmira, N.Y · UCCL01086
- Samuel L. Clemens to John C. Day and Alice H. Day, 27 September 1876 · Hartford, Conn · UCCL01368
- Samuel L. and Olivia L. Clemens to the Saturday Morning Club, 25 March 1878 · Hartford, Conn · UCCL01549
- Samuel L. Clemens to the Saturday Morning Club, 1–11 June 1880 · Hartford, Conn · UCCL10480
- SLC to Laura Taft, 1 January 1883 · Hartford, Conn · UCCL11267
- SLC to Isabella B. Hooker, 27 May 1884 · Hartford, Conn · UCCL10482
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