Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "Industrial Production - Indexes and Gross Value," in Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "April 1997," Federal Reserve Bulletin (April 1997) : 177-178. https://fraser.stlouisfed.org/title/62/item/20899/toc/294411 , accessed on May 4, 2024.