Powell, Oliver S., 1896-1963 , Board of Governors of the Federal Reserve System (U.S.), 1935- , Federal Reserve Bank of Minneapolis and Federal Reserve Board, 1914-1935 "Forecasting Farm Tractor Sales in North Dakota." March 1, 1929, https://fraser.stlouisfed.org/title/944/item/36653, accessed on August 29, 2024.