Sources: NNAL
- SLC to Courtlandt Palmer, 20 January 1886 · Hartford, Conn · UCCL03357
- SLC to Richard Watson Gilder, 24 August 1888 · Elmira, N.Y · UCCL03753
- SLC to Robert U. Johnson, 10 December 1904 · New York, N.Y · UCCL06958
- SLC per Isabel V. Lyon to Edmund C. Stedman, 21 December 1904 · New York, N.Y · UCCL06961
- SLC per Isabel V. Lyon to American Academy of Arts and Letters, 24 January 1905 · New York, N.Y · UCCL06984
- Isabel V. Lyon for SLC to Robert U. Johnson, 7 April 1905 · New York, N.Y · UCCL07027
- SLC to Robert U. Johnson, 28 April 1905 · New York, N.Y · UCCL07034
- SLC to Robert U. Johnson, 3 May 1905 · New York, N.Y · UCCL07039
- SLC to Hamlin Garland, 30 June 1905 · Dublin, N.H · UCCL07075
- Isabel V. Lyon for SLC to Robert U. Johnson, 29 September 1905 · Dublin, N.H · UCCL07153
- SLC per Isabel V. Lyon to Robert U. Johnson, 19 December 1905 · New York, N.Y · UCCL07266
- SLC per Isabel V. Lyon to Robert U. Johnson, 31 May 1907 · Tuxedo Park, N.Y · UCCL07737
- Isabel V. Lyon for SLC to Robert U. Johnson, 1 January 1908 · New York, N.Y · UCCL12340
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