United States. Bureau of Economic Analysis. "September 1930," Survey of Current Business (September 1930). https://fraser.stlouisfed.org/title/46/item/9253, accessed on April 12, 2024.
United States. Bureau of Economic Analysis. "September 1930," Survey of Current Business (September 1930). https://fraser.stlouisfed.org/title/46/item/9253, accessed on April 12, 2024.