Sources: NMh
- SLC to Poultney Bigelow, 9 November 1891 · Berlin, Germany · UCCL04250
- SLC to Poultney Bigelow, 6 May 1892 · Florence, Italy · UCCL04288
- SLC to Poultney Bigelow, 1 August 1893 · Krankenheil, Germany · UCCL04429
- SLC to Poultney Bigelow, 14 January 1894 · New York, N.Y · UCCL04672
- SLC to Poultney Bigelow, 11 February 1894 · New York, N.Y · UCCL04691
- SLC to Poultney Bigelow, 25 April 1895 · Paris, France · UCCL04870
- SLC to Poultney Bigelow, 2 May 1895 · Paris, France · UCCL04875
- SLC to Poultney Bigelow, 16 July 1896 · Cape Town, Cape Colony · UCCL05085
- SLC to Poultney Bigelow, October 1896 · London, England · UCCL05122
- SLC to Poultney Bigelow, 29 July 1898 · Kaltenleutgeben, Austria · UCCL05417
- SLC to Poultney Bigelow, 19 December 1898 · Vienna, Austria · UCCL05481
- SLC to Poultney Bigelow, March 1899 · Vienna, Austria · UCCL05553
- SLC to Poultney Bigelow, 22 March 1899 · Vienna, Austria · UCCL05565
- SLC to Poultney Bigelow and Edith E. Bigelow, 2 April 1899 · Vienna, Austria · UCCL05573
- SLC to Poultney Bigelow, 1 June 1899 · London, England · UCCL05628
- SLC to Poultney Bigelow, 10 July–27 September 1899 · Sanna, Sweden · UCCL05661
- SLC to Poultney Bigelow, 30 July 1899 · Sanna, Sweden · UCCL05659
- SLC to Poultney Bigelow, 1 September 1899 · Sanna, Sweden · UCCL05669
- SLC to Poultney Bigelow, 14 October 1899 · London, England · UCCL05689
- SLC to Poultney Bigelow, 10 November 1899 · London, England · UCCL10947
- SLC to Poultney Bigelow, 10 November 1899 · London, England · UCCL05702
- SLC to Poultney Bigelow, 1899, London, England · UCCL05527
- SLC to Poultney Bigelow, 3 February 1900 · London, England · UCCL05756
- SLC to Poultney Bigelow, 27–31 March 1900 · London, England · UCCL05732
- SLC to Poultney Bigelow, 1 April 1900 · London, England · UCCL05734
- SLC to Poultney Bigelow, 10 May 1900 · London, England · UCCL05804
- SLC to Poultney Bigelow, 25 July 1900 · London, England · UCCL05836
- SLC to Poultney Bigelow, 2 May 1902 · Riverdale, N.Y · UCCL06331
- SLC to Poultney Bigelow, 27 October 1902 · Riverdale, N.Y · UCCL06474
- SLC to Poultney Bigelow, 15 November 1902 · Riverdale, N.Y · UCCL06488
- SLC to Poultney Bigelow, 17 January 1903 · Riverdale, N.Y · UCCL06567
- SLC to Poultney Bigelow, 21 February 1903 · Riverdale, N.Y · UCCL06584
- SLC to Poultney Bigelow, 17 April 1903 · Riverdale, N.Y · UCCL06622
- SLC to Poultney Bigelow, 4 May 1904 · Florence, Italy · UCCL06827
- SLC to Poultney Bigelow, 18 May 1909 · Redding, Conn · UCCL08398
- SLC to Poultney Bigelow, 27 May 1909 · Redding, Conn · UCCL08405
- SLC to Poultney Bigelow, Unknown date · Unknown place · UCCL05733
- SLC to Poultney Bigelow, 1900 · Unknown place · UCCL05731
1