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. "December 1939," Federal Reserve Bulletin (December 1939) : 92-92. https://fraser.stlouisfed.org/title/62/item/21020/toc/217017 , accessed on May 3, 2024.