Addressees: Clemens, Katharine B
- SLC, OLC to Katharine B. Clemens, 29 March 1899 · Vienna, Austria · UCCL05570
- SLC to James R. and Katharine B. Clemens, 3 May 1899 · Vienna, Austria · UCCL08855
- OLC to Katharine B. Clemens, 24 June 1899 · London, England · UCCL02479
- OLC to Katharine B. Clemens, 8 December 1899 · London, England · UCCL08853
- OLC to James R. and Katharine B. Clemens, 27 March 1900 · London, England · UCCL10949
- SLC to James R. and Katharine B. Clemens, 28 March 1900 · London, England · UCCL08858
- OLC to Katharine B. Clemens, 1 May 1900 · London, England · UCCL08862
- OLC to Katharine B. Clemens, 10 May–24 May 1900 · London, England · UCCL08861
- OLC to Katharine B. Clemens, 29 May 1900 · London, England · UCCL08863
- SLC to Katharine B. Clemens, 13 June 1900 · London, England · UCCL05820
- OLC to Katharine B. Clemens, 12 July 1900 · London, England · UCCL02663
- Jean Clemens to Katharine B. Clemens, 15 July 1900 · London, England · UCCL08864
- OLC to Katharine B. Clemens, 22 August 1900 · London, England · UCCL08866
- OLC to Katharine B. Clemens, 6 October 1900 · London, England · UCCL10114
- OLC to Katharine B. Clemens, 4 May 1902 · Riverdale, N.Y · UCCL08878
- OLC to Katharine B. Clemens, 17 May 1902 · Riverdale, N.Y · UCCL06340
- OLC to Katharine B. Clemens, 27 May 1902 · Riverdale, N.Y · UCCL08879
- SLC to Katharine B. Clemens, June 1902 · Unknown place · UCCL11260
- SLC to Katharine B. Clemens, June 1902 · Unknown place · UCCL09369
- SLC to James R. Clemens and Katharine B. Clemens, 22 August 1902 · York Harbor, Me · UCCL06413
- SLC to Katharine B. Clemens, 27 August 1902 · York Harbor, Me · UCCL06416
- SLC to Katharine B. Clemens, 26 September 1902 · York Harbor, Me · UCCL06443
- SLC to Katharine B. Clemens, 31 August 1905 · Dublin, N.H · UCCL07121
- SLC to Katharine B. Clemens, 16 October 1906 · Dublin, N.H · UCCL07549
- SLC per Isabel V. Lyon to Katharine B. Clemens, 5 October 1907 · Tuxedo Park, N.Y · UCCL08894
- SLC per Isabel V. Lyon to Katharine B. Clemens, 13 August 1908 · Redding, Conn · UCCL08900
- SLC per Isabel V. Lyon to Katharine B. Clemens, 20 August 1908 · Redding, Conn · UCCL08901
- SLC per Albert Bigelow Paine to Katharine B. Clemens, 26 December–16 March 1910 · Redding, Conn · UCCL11005
- SLC to Katharine B. Clemens, 24 March 1910 · Hamilton, Bermuda · UCCL08575
- SLC to James R. and Katharine B. Clemens, 25 December n.y. · Unknown place · UCCL08390
- OLC to Katharine B. Clemens, Unknown date · Unknown place · UCCL10154
- OLC to Katharine B. Clemens, Unknown date · Unknown place · UCCL08417
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