Sources: NNAF
- SLC to Helen Keller, 17 March 1903 · Riverdale, N.Y · UCCL06599
- SLC to Helen Keller, 26 July 1904 · Lee, Mass · UCCL06904
- Jean Clemens for SLC to Anne S. Macy, 19 January 1905 · New York, N.Y · UCCL10678
- SLC to Helen Keller, 6 December 1905 · New York, N.Y · UCCL10680
- SLC to Helen Keller, 23 December 1906 · New York, N.Y · UCCL07595
- SLC to Helen Keller, 14 November 1908 · Redding, Conn · UCCL10684
- SLC per Isabel V. Lyon to Helen Keller, 22 November 1908 · Redding, Conn · UCCL10683
- SLC to Helen Keller, 8 January 1909 · Redding, Conn · UCCL10681
- SLC to Anne S. Macy, 8 January 1909 · Redding, Conn · UCCL10682
- SLC to Anne S. Macy, 11 January 1909 · Redding, Conn · UCCL09387
- SLC to John A. Macy, 25 February 1909 · Redding, Conn · UCCL10685
- SLC to John A. Macy, 27 March 1909 · Redding, Conn · UCCL10686
- SLC to John A. Macy, 8 April 1909 · Redding, Conn · UCCL10687
- SLC to Helen Keller, 29 June 1909 · Redding, Conn · UCCL08429
- SLC to Helen Keller, 26 December–26 January 1910 · Hamilton, Bermuda · UCCL10688
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