Guide to the Hertha Sponer papers, Duke University Archives, David M. Rubenstein Rare Book & Manuscript Library, Duke University, viewed 2024 Nov. 20. (Hedwig Kohn, colleague of Hertha Sponer in Duke University Department of Physics) https://idn.duke.edu/ark:/87924/m1ct67

Ancestrylibrary.com North Carolina, U.S., Death Certificates, 1976 (Hedwig Kohn, b. 5 April 1887, d. 26 Nov. 1964, Durham, N.C., research associate in the Duke University Department of Physics)