Sources: CStbK
- SLC to Irving Putnam, 26 January 1889 · Hartford, Conn · UCCL03854
- SLC to Clara L. Clemens, 20 July 1890 · Hartford, Conn · UCCL04064
- SLC to Francis E. Bliss, 1 May 1894 · New York, N.Y · UCCL12347
- SLC to Unidentified, 15 November 1897 · Vienna, Austria · UCCL11358
- SLC to Charles J. Langdon, 5 August 1898 · Kaltenleutgeben, Austria · UCCL11311
- SLC to Fanny Clemons, 13 June 1900 · London, England · UCCL09510
- SLC to ?Stephen Coleridge, 17 December 1903 · Florence, Italy · UCCL13475
1