Addressees: Mackey, Robert K
- SLC to Robert K. Mackey, 21 June 1904 · Florence, Italy · UCCL06778 CU-MARK
- SLC per Isabel V. Lyon to Robert K. Mackey, 22 December 1905 · New York, N.Y · UCCL10841 MH-H
- SLC per Isabel V. Lyon to Robert K. Mackey, 23 December 1905 · New York, N.Y · UCCL10839 MH-H
- Isabel V. Lyon for SLC to Robert K. Mackey, 7 March 1906 · New York, N.Y · UCCL10840 MH-H
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