Sources: CL3
- SLC to Robert Barr, 16 September 1897 · Weggis, Switzerland · UCCL10600 CL3
- SLC to Augustus T. Gurlitz, 3 December 1900 · New York, N.Y · UCCL11868 CL3
- SLC to Augustus T. Gurlitz, 13 December 1900 · New York, N.Y · UCCL11869 CL3
- SLC to Charles A. Slosson, December 1905 · New York, N.Y · UCCL12434 CL3
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