Sources: WU-MU
- Samuel L. Clemens to Henry M. Crane, 20 May 1867 · New York, N.Y · UCCL02779
- Samuel L. Clemens to Elisha Bliss, Jr., 5 May 1868 · San Francisco, Calif · UCCL02731
- Samuel L. Clemens to Henry M. Crane, 3 September 1868 · Elmira, N.Y · UCCL02749
- Samuel L. Clemens to Elisha Bliss, Jr., 3 September 1868 · Elmira, N.Y · UCCL02748
- Samuel L. Clemens to Elisha Bliss, Jr., 15 August 1869 · Buffalo, N. Y · UCCL00333
- Samuel L. Clemens to Mathew B. Cox, 24 September 1869 · Buffalo, N.Y · UCCL10990
- Samuel L. Clemens to Frank Fuller, 26 April 1870 · Buffalo, N. Y · UCCL00460
- Samuel L. Clemens to Elisha Bliss, Jr., 5 May 1870 · Elmira, N.Y · UCCL00461
- Samuel L. Clemens to Elisha Bliss, Jr., 27 June 1870 · Elmira, N.Y · UCCL00483
- Samuel L. Clemens to James Redpath, 3 December 1870 · Buffalo, N.Y · UCCL00549
- Samuel L. Clemens to James Redpath and George L. Fall, 11 October 1871 · Hartford, Conn · UCCL00659
- Samuel L. Clemens to Elisha Bliss, Jr., 20 March 1872 · Elmira, N. Y · UCCL11848
- Samuel L. Clemens to Elisha Bliss, Jr., 3 May 1873 · Hartford, Conn · UCCL00912
- Samuel L. Clemens to Francis D. Finlay, 12 January 1874 · Liverpool, England · UCCL01040
- Samuel L. Clemens to Francis D. Finlay, 23 April 1874 · Elmira, N. Y · UCCL01078
- Samuel L. Clemens to William A. Seaver, 1 May 1874 · Elmira, N.Y · UCCL01081
- Samuel L. Clemens to William A. Seaver, 20 May 1874 · Elmira, N.Y · UCCL01090
- Samuel L. Clemens to Frank Fuller, 6 September 1874 · Elmira, N.Y · UCCL01124
- Samuel L. Clemens to William A. Seaver, 25 September 1874 · Hartford, Conn · UCCL01100
- Samuel L. Clemens to Francis D. Finlay, 10 November 1874 · Hartford, Conn · UCCL01146
- Samuel L. Clemens to William A. Seaver, 26 February 1875 · Hartford, Conn · UCCL01198
- Samuel L. Clemens to William A. Seaver, 6 March 1875 · Hartford, Conn · UCCL01204
- Samuel L. Clemens to William A. Seaver, 10 November 1875 · Hartford, Conn · UCCL07707
- Samuel L. Clemens to William A. Seaver, 5 December 1875 2nd of 2 · Hartford, Conn · UCCL01286
- Samuel L. Clemens to William A. Seaver, 16 September 1876 · Hartford, Conn · UCCL01365
- Samuel L. Clemens to Francis E. Bliss, 9 February 1879 · Munich, Germany · UCCL01629
- Samuel L. Clemens to Francis E. Bliss, 10 June 1879 · Paris, France · UCCL01664
- Samuel L. Clemens to Frank Fuller, 22 April 1880 · Hartford, Conn · UCCL01791
- Samuel L. Clemens to Francis E. Bliss, 23 October 1880 · Hartford, Conn · UCCL01844
- SLC to Francis E. Bliss, 30 May 1881 · Hartford, Conn · UCCL01960
- SLC to Frank Fuller, 5 July 1882 · Hartford, Conn · UCCL02231
- SLC to Francis E. Bliss, 9 September 1882 · Elmira, N.Y · UCCL02266
- SLC to Frank Fuller, 18 October 1884 · Hartford, Conn · UCCL03009
- SLC to Laurence Hutton, 7 December 1885 · Hartford, Conn · UCCL03326
- SLC to Francis D. Finlay, 17 May 1887 · Hartford, Conn · UCCL03573
- SLC to Francis D. Finlay, 17 August 1889 · Elmira, N.Y · UCCL03927
- SLC to Frank Fuller, 12 October 1889 · Hartford, Conn · UCCL03951
- SLC to Frank Fuller, 6 March 1894 · New York, N.Y · UCCL04707
- SLC to Francis E. Bliss, 29 October 1894 · Rouen, France · UCCL04804
- SLC to John D. Adams, 23 January 1895 · Paris, France · UCCL04837
- SLC to Frank Fuller, 5 March 1895 · New York, N.Y · UCCL04846
- SLC to J. Henry Harper, 23 April 1895 · Paris, France · UCCL04869
- SLC to Francis E. Bliss, 1 July 1895 · Elmira, N.Y · UCCL04920
- SLC to Players Club secretary, 4 August 1895 · Helena, Mont · UCCL04939
- SLC to Frank Fuller, 27 May 1897 · London, England · UCCL05216
- SLC to Frank Fuller, 3 June 1897 · London, England · UCCL05223
- SLC to Frank Fuller, 2 July 1897 · London, England · UCCL05248
- SLC to Francis E. Bliss, 21 June 1898 · Kaltenleutgeben, Austria · UCCL05402
- SLC to Francis E. Bliss, 20 July 1898 · Kaltenleutgeben, Austria · UCCL05412
- SLC to Francis E. Bliss, 28 August 1898 · Kaltenleutgeben, Austria · UCCL05424
- SLC to Francis D. Finlay, 25 April 1900 · London, England · UCCL05799
- SLC to John K. Bangs, 22 October 1900 · New York, N.Y · UCCL05882
- SLC to Francis E. Bliss, March 1901 · New York, N.Y · UCCL06010
- SLC to Francis E. Bliss, 18 March 1901 · New York, N.Y · UCCL06019
- SLC to Francis E. Bliss, 27 March 1901 · New York, N.Y · UCCL06029
- SLC to Francis E. Bliss, 13 July 1901 · Saranac Lake, N.Y · UCCL06088
- SLC to Frank Fuller, 4 December 1901 · Riverdale, N.Y · UCCL06181
- SLC to Jules Hart, 16 December 1901 · Riverdale, N.Y · UCCL06190
- SLC to Jules Hart, 17 December 1901 · Riverdale, N.Y · UCCL06191
- SLC to Francis E. Bliss, 8 October 1902 · York Harbor, Me · UCCL06456
- SLC to Francis E. Bliss, 25 December 1902 · Riverdale, N.Y · UCCL06526
- SLC to Francis E. Bliss, 28 April 1903 · Riverdale, N.Y · UCCL06636
- SLC to Francis H. Skrine, 17 December 1903 · Florence, Italy · UCCL06769
- SLC to Francis E. Bliss, 9 September 1904 · New York, N.Y · UCCL06918
- SLC to Joseph H. Twichell, 1 and 2 June 1905 · Dublin, N.H · UCCL07055
- SLC to George B. Harvey, 30 July 1905 · Dublin, N.H · UCCL07098
- Clara L. Clemens to David A. Munro, 25 August 1906 · New York, N.Y · UCCL07099
- SLC to Thomas S. Barbour, 27 October 1905 · Boston, Mass · UCCL07188
- SLC to Jay Bean Bassett, December 1905 · New York, N.Y · UCCL13594
- SLC to Louis Windmuller, 12 December 1905 · New York, N.Y · UCCL07248
- SLC to Norman D. Bassett, April 1906 · New York, N.Y · UCCL10736
- SLC to F. N. Otremba, 30 November 1908 · Redding, Conn · UCCL08163
- SLC to Albert Bigelow Paine, 14 February 1910 · Hamilton, Bermuda · UCCL08556
- SLC to Frank Fuller, 2 July n.y. · Elmira, N.Y · UCCL09053
- SLC to Century editor, Unknown date, Hartford, Conn · UCCL09059
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