Senders: Doubleday, Frank N.
- Frank N. Doubleday to SLC, 29 October 1900 · New York, N.Y. · UCLC32982 CU-MARK
- Frank N. Doubleday to SLC, 29 May 1906 · UCLC50234 CU-MARK
- Frank N. Doubleday to SLC, 17 December 1906 · UCLC35776 CU-MARK
- Ralph Danenhower for Frank N. Doubleday to SLC, 29 May 1907 · UCLC36447 CU-MARK
- Frank N. Doubleday to SLC, 14 June 1907 · UCLC36494 CU-MARK
- Frank N. Doubleday to SLC, 20 August 1907 · New York, N.Y. · UCLC37162 CU-MARK
- Frank N. Doubleday to SLC, 27 August 1907 · New York, N.Y. · UCLC37181 CU-MARK
- Frank N. Doubleday to SLC, 3 September 1907 · New York, N.Y. · UCLC37202 CU-MARK
- Frank N. Doubleday to SLC, 19 September 1907 · New York, N.Y. · UCLC37251 CU-MARK
- Frank N. Doubleday to SLC, 16 October 1907 · New York, N.Y. · UCLC37356 CU-MARK
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