Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "Industrial Production, by Industries (Unadjusted Indexes)," in Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "May 1939," Federal Reserve Bulletin (May 1939) : 73-73. https://fraser.stlouisfed.org/title/62/item/21013/toc/249127 , accessed on April 18, 2024.