Board of Governors of the Federal Reserve System (U.S.), 1935-. "Market Groupings, Seasonally Adjusted," in Board of Governors of the Federal Reserve System (U.S.), 1935-. "April 15, 1980," G.12.3 Industrial Production (1980-04-15) : 3-3. https://fraser.stlouisfed.org/title/55/item/59781/toc/471954 , accessed on May 9, 2024.