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
- SLC to Charles Warren Stoddard, October 1890· Hartford, Conn · UCCL09306
- SLC to ? Hardy, 3 February 1894 · New York, N.Y · UCCL04687
- SLC to OLC, 25 April 1894 · New York, N.Y · UCCL11798
- SLC to Charles E. Wood, 21 March 1900 · London, England · UCCL05779
- SLC to Paschal H. Coggins, 16 February 1901 · New York, N.Y · UCCL06000
- SLC to Charles E. Wood, 23 February 1901 · New York, N.Y · UCCL06009
- SLC to Harry L. Wilson, 23 June 1902 · Riverdale, N.Y · UCCL06376
- SLC to Harry L. Wilson, 28 June 1902 · York Harbor, Me · UCCL06378
- SLC to Charles E. Wood, 31 October 1904 · New York, N.Y · UCCL06941
- SLC to Wallace Irwin, 8 March 1909 · Redding, Conn · UCCL00540
- SLC to Unidentified, Unknown date · Unknown place · UCCL11230
- SLC to Unidentified, Unknown date · Unknown place · UCCL11229
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