Sproul, Allan, 1896-1978. Letter, Allan Sproul to Alfred Hayes, . https://fraser.stlouisfed.org/archival/1174/item/3394, accessed on April 18, 2024.
Sproul, Allan, 1896-1978. Letter, Allan Sproul to Alfred Hayes, . https://fraser.stlouisfed.org/archival/1174/item/3394, accessed on April 18, 2024.