Addressees: Harper & Brothers
- SLC to Harper & Brothers, 21 November 1898 · Vienna, Austria · UCCL05419 CU-MARK
- SLC to Harper & Brothers, 12 December 1898 · Vienna, Austria · UCCL05479 CU-MARK
- SLC to Harper & Brothers, 1 October 1899 · London, England · UCCL11064 CtY
- SLC to Harper & Brothers, 23 January 1900 · London, England · UCCL09394 CBev2
- SLC to Harper & Brothers, August 1900 · London, England · UCCL10112 CU-MARK
- SLC to Harper & Brothers, 19 January 1901 · New York, N.Y · UCCL10115
- SLC to Harper & Brothers, 4 September 1901 · Saranac Lake, N.Y · UCCL11227
- SLC per Isabel V. Lyon to Harper & Brothers, 27 January 1903 · Riverdale, N.Y · UCCL06572 CU-MARK
- SLC to Harper & Brothers, 13 March 1903 · Riverdale, N.Y · UCCL06598 CU-MARK
- SLC, OLC to Harper & Brothers, 23 October 1903 · New York, N.Y · UCCL06752 ViU
- SLC to Harper & Brothers, November 1903 · Unknown place · UCCL12494
- SLC to Harper & Brothers, 1 December 1903 · Florence, Italy · UCCL06763 CU-MARK
- SLC to Harper & Brothers, 1904 · Unknown place · UCCL06925 NRU
- SLC to Harper & Brothers, 29 January 1905 · New York, N.Y · UCCL06990 CU-MARK
- SLC to Harper & Brothers, 7 June 1905 · Dublin, N.H · UCCL07058 CU-MARK
- Isabel V. Lyon for SLC to Harper & Brothers, 29 September 1905 · Dublin, N.H · UCCL07152 CU-MARK
- SLC to Harper & Brothers, 9 October 1905 · Dublin, N.H · UCCL07169 CU-MARK
- SLC to Harper & Brothers, 1905 · Unknown place · UCCL06969 CU-MARK
- SLC per Isabel V. Lyon to Harper & Brothers, 24 February 1906 · New York, N.Y · UCCL12139 CU-MARK
- SLC per Isabel V. Lyon to Harper & Brothers, 31 March 1906 · New York, N.Y · UCCL07406 CU-MARK
- Isabel V. Lyon for SLC to Harper & Brothers, 15 June 1906 · Dublin, N.H · UCCL07456 CU-MARK
- SLC per Isabel V. Lyon to Harper & Brothers, 17 August 1906 · Dublin, N.H · UCCL07501 CU-MARK
- SLC per Isabel V. Lyon to Harper & Brothers, 28 December 1906 · New York, N.Y · UCCL07602 CU-MARK
- SLC to Harper & Brothers, 2 April 1907 · New York, N.Y · UCCL07684 CU-MARK
- SLC to Harper & Brothers, 17 April 1907 · New York, N.Y · UCCL02690 NNC, CU-MARK
- SLC per Isabel V. Lyon to Harper & Brothers, 29 May 1907 · Tuxedo Park, N.Y · UCCL07736 CU-MARK
- SLC to Harper & Brothers, Unknown date · Unknown place · UCCL07614 CU-MARK
- SLC to Harper & Brothers, 11 September 1909 · Redding, Conn · UCCL12912 CU-MARK
- SLC to Harper & Brothers, 3 November 1909 · Redding, Conn · UCCL11108
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