Sources: CU-BANC
- Samuel L. Clemens to William K. Cutler, 28 May 1864 · Virginia City, Nev. Terr · UCCL00083
- Samuel L. Clemens to William Wright (Dan De Quille), 15 July 1864 · San Francisco, Calif · UCCL00084
- Samuel L. Clemens to Charles Warren Stoddard with a note to the Postmaster, 27 April 1867 · New York, N.Y · UCCL00125
- Samuel L. Clemens to William Wright (Dan De Quille), 6? February 1870 · Buffalo, N.Y · UCCL00399
- Samuel L. Clemens to William Wright (Dan De Quille), 24 March 1875 · Hartford, Conn · UCCL01215
- Samuel L. Clemens to William Wright (Dan De Quille), 29 March 1875 · Hartford, Conn · UCCL01217
- Samuel L. Clemens to William Wright (Dan De Quille), 29 March and 4 April 1875 · Hartford, Conn · UCCL11611
- SLC to Charles T. Palmer, 3 October 1882 · Hartford, Conn · UCCL02284
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