Sources: MoSW
- Samuel L. Clemens to John J. Murphy, 1 June 1869 · Elmira, N. Y · UCCL00310 MoSW
- Samuel L. Clemens to Charles Henry Webb, 14 January 1871 · Buffalo, N.Y · UCCL00558 MoSW
- Samuel L. Clemens to the Editor of Every Saturday (Thomas Bailey Aldrich), 15 January 1871 · Buffalo, N.Y · UCCL00559 MoSW
- Samuel L. Clemens to John A. Lant, 28 September 1871 · Buffalo, N.Y · UCCL00655 MoSW
- Samuel L. Clemens to Henry Lee, 8 October 1873 · London, England · UCCL00970 MoSW, CU-MARK
- Samuel L. Clemens to George H. Fitzgibbon, 9 December 1873 · London, England · UCCL00995 MoSW
- Samuel L. Clemens to Frank Fuller, 31 January 1874 · Hartford, Conn · UCCL01041 MoSW
- Samuel L. Clemens to Thomas Bailey Aldrich, 15 and 16 March 1874 · Hartford, Conn · UCCL01063 MoSW
- Samuel L. Clemens to Annie W. Fuller, 7 April 1874 · Hartford, Conn · UCCL01071 MoSW
- Samuel L. Clemens to Unidentified, 5 October 1875 · Hartford, Conn · UCCL01268 MoSW
- Samuel L. Clemens to Frank Fuller, 5 April 1878 · New York, N.Y · UCCL01552 MoSW
- Samuel L. Clemens to Robert M. Hooper, 12 May? 1879 · Paris, France · UCCL08942 MoSW
- Samuel L. Clemens to Frank Fuller with a note to Thomas L. James, New York Postmaster, 18 November 1879· Hartford, Conn · UCCL01721 MoSW
- Samuel L. Clemens to Charles Warren Stoddard, 17 June 1880 · Elmira, N.Y · UCCL01813 MoSW
- Samuel L. Clemens to Frank Fuller, 2 October 1880 · Hartford, Conn · UCCL01835 MoSW
- SLC to James R. Osgood, 8 December 1881 · Montreal, Canada · UCCL02112 MoSW
- SLC to Lester Wallack, 14 January 1887 · Hartford, Conn · UCCL03507 MoSW
- SLC to H. F. Gordon Forbes, 15 September 1899 · Sanna, Sweden · UCCL05673 MoSW
- SLC to H. F. Gordon Forbes, 1 October 1899 · London, England · UCCL05685 MoSW
- SLC to H. F. Gordon Forbes, 10 November 1899 · London, England · UCCL05703 MoSW
- SLC to Francis E. Bliss, 10 January 1902 · Riverdale, N.Y · UCCL06240 MoSW
- SLC to Frederick A. Duneka, 30 December 1903 · Florence, Italy · UCCL06773 MoSW
- SLC to Andrew Carnegie, 28 April 1905 · New York, N.Y · UCCL07035 MoSW
- SLC to ? Martin, 5 August 1907 · Tuxedo Park, N.Y · UCCL09257 MoSW
- SLC to Frances F. Cleveland, 25 June 1908 · Redding, Conn · UCCL08042 MoSW
- SLC to Frederick A. Duneka, 30 June 1909 · Redding, Conn · UCCL08430 MoSW
- SLC to Associated Press, 24 December 1909 · Redding, Conn · UCCL08516 MoSW
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