Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "Freight-Car Loadings: Revised Indexes," in Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "February 1931," Federal Reserve Bulletin (February 1931) : 60-61. https://fraser.stlouisfed.org/title/62/item/20710/toc/85095 , accessed on April 18, 2024.