Sources: NjP
- Samuel L. Clemens to James R. Osgood, 31 March 1872 · Elmira, N.Y · UCCL00739
- Samuel L. Clemens to Thomas Nast, 10 December 1872 · Hartford, Conn · UCCL00843
- Samuel L. Clemens to Charles Dudley Warner, 10? July 1873 · London, England · UCCL00951
- Samuel L. Clemens to Andrew Chatto, 24 March 1879 · Paris, France · UCCL01643
- Samuel L. Clemens to Francis E. Bliss, 10 May 1879 · Paris, France · UCCL01653
- SLC to Unidentified, 5 July 1881 · Branford, Conn · UCCL01982
- SLC to Philip A. Rollins, 31 December 1881 · Hartford, Conn · UCCL10694
- SLC to James R. Osgood, 13 March 1883 · Hartford, Conn · UCCL08973
- SLC to Laurence Hutton, 22 April 1883 · Hartford, Conn · UCCL02373
- SLC to Laurence Hutton, 20 December 1883 · Hartford, Conn · UCCL02871
- SLC to Laurence Hutton, 12 February 1884 · Hartford, Conn · UCCL02915
- SLC to Laurence Hutton, 19 February 1884 · Hartford, Conn · UCCL02921
- SLC to Laurence Hutton, 7 March 1884 · Hartford, Conn · UCCL02934
- SLC to James R. Osgood, 24 May 1884 · Hartford, Conn · UCCL02985
- SLC to Laurence Hutton, 22 December 1884 · Hartford, Conn · UCCL03065
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