Sources: CU-BANC
- Samuel L. Clemens to William K. Cutler, 28 May 1864 · Virginia City, Nev. Terr · UCCL00083 CU-BANC
- Samuel L. Clemens to William Wright (Dan De Quille), 15 July 1864 · San Francisco, Calif · UCCL00084 CU-BANC
- Samuel L. Clemens to Charles Warren Stoddard with a note to the Postmaster, 27 April 1867 · New York, N.Y · UCCL00125 CSmH, CU-BANC
- Samuel L. Clemens to William Wright (Dan De Quille), 6? February 1870 · Buffalo, N.Y · UCCL00399 CU-BANC
- Samuel L. Clemens to William Wright (Dan De Quille), 24 March 1875 · Hartford, Conn · UCCL01215 CU-BANC
- Samuel L. Clemens to William Wright (Dan De Quille), 29 March 1875 · Hartford, Conn · UCCL01217 CU-BANC
- Samuel L. Clemens to William Wright (Dan De Quille), 29 March and 4 April 1875 · Hartford, Conn · UCCL11611 IaWl2, CU-BANC
- SLC to Charles T. Palmer, 3 October 1882 · Hartford, Conn · UCCL02284 CU-BANC
- SLC to Charles Warren Stoddard, October 1890· Hartford, Conn · UCCL09306 CU-BANC, CU-MARK
- SLC to ? Hardy, 3 February 1894 · New York, N.Y · UCCL04687 CU-BANC
- SLC to OLC, 25 April 1894 · New York, N.Y · UCCL11798 CU-BANC
- SLC to Charles E. Wood, 21 March 1900 · London, England · UCCL05779 CU-BANC
- SLC to Paschal H. Coggins, 16 February 1901 · New York, N.Y · UCCL06000 CU-BANC
- SLC to Charles E. Wood, 23 February 1901 · New York, N.Y · UCCL06009 CU-BANC
- SLC to Harry L. Wilson, 23 June 1902 · Riverdale, N.Y · UCCL06376 CU-BANC
- SLC to Harry L. Wilson, 28 June 1902 · York Harbor, Me · UCCL06378 CU-BANC
- SLC to Charles E. Wood, 31 October 1904 · New York, N.Y · UCCL06941 CU-BANC
- SLC to Wallace Irwin, 8 March 1909 · Redding, Conn · UCCL00540 CU-BANC
- SLC to Unidentified, Unknown date · Unknown place · UCCL11230 CU-BANC
- SLC to Unidentified, Unknown date · Unknown place · UCCL11229 CU-BANC
- Maynard Shipley to SLC, Unknown date · UCLC46745 CU-BANC
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