Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "Freight-Car Loadings, by Classes," in Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "May 1940," Federal Reserve Bulletin (May 1940) : 80-80. https://fraser.stlouisfed.org/title/62/item/21025/toc/302923 , accessed on May 11, 2024.