Helfferich, Reginald H. (1905-1981), Ms. Coll. 006. E&R Library & Archives.
Helfferich, Reginald H. (1905-1981), Ms. Coll. 006. E&R Library & Archives. https://erhistoricalsociety.libraryhost.com/repositories/2/resources/3261 Accessed July 27, 2025.
