Sources: BmuHA
- SLC to Helen S. Allen, 19 May 1908 · New York, N.Y · UCCL11784
- SLC to Helen S. Allen, 2 June 1908 · New York, N.Y · UCCL11783
- SLC to Helen S. Allen, 13 August 1908 · Redding, Conn · UCCL11334
- SLC to Helen S. Allen, 7 October 1908 · Redding, Conn · UCCL11782
- SLC to Helen S. Allen, 10 September 1909 · Redding, Conn · UCCL11796
- SLC to Helen S. Allen, 21 September 1909 · Redding, Conn · UCCL11781
- SLC to Helen S. Allen, 1 October 1909 · Redding, Conn · UCCL11785
- SLC to Helen S. Allen, 7 October 1909 · Redding, Conn · UCCL11829
- SLC to Helen S. Allen, 7 October 1909 · Redding, Conn · UCCL11697
- SLC to Helen S. Allen, 12 October 1909 · Redding, Conn · UCCL11786
- SLC to Helen S. Allen, 30 October 1909 · Redding, Conn · UCCL11787
- SLC to Helen S. Allen, 18 December–20 December 1909 · SS Bermudian · UCCL11780
- SLC to Marion S. Allen, 19 December 1909 · SS Bermudian · UCCL11779
- SLC to William H. Allen, 22 December 1909 · Redding, Conn · UCCL11793
- Albert B. Paine for SLC to William H. Allen, 3 January 1910 · Redding, Connecticut · UCCL13056
- Albert Bigelow Paine for SLC to William H. Allen per Telegraph Operator, 5 January 1910 · New York, New York · UCCL13057
- SLC to Helen S. Allen, 14 February 1910 · Hamilton, Bermuda · UCCL11111
- SLC to Barnum & Bailey, 3 April 1910 · Hamilton, Bermuda · UCCL11112
- Clara C. Gabrilowitsch to Marion Schuyler Allen, 18 April 1910 · Redding, Conn · UCCL11832
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