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. "March 1940," Federal Reserve Bulletin (March 1940) : 63-63. https://fraser.stlouisfed.org/title/62/item/21023/toc/383800 , accessed on April 18, 2024.