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. "May 1998," Federal Reserve Bulletin (May 1998) : 129-130. https://fraser.stlouisfed.org/title/62/item/20912/toc/83194 , accessed on May 3, 2024.