Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "Industrial Production, by Industries (Adjusted Indexes)," in Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "May 1938," Federal Reserve Bulletin (May 1938) : 57-57. https://fraser.stlouisfed.org/title/62/item/21001/toc/276707 , accessed on April 19, 2024.