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-. "February 17, 1981," G.12.3 Industrial Production (1981-02-17) : 4-4. https://fraser.stlouisfed.org/title/55/item/59641/toc/472139 , accessed on March 28, 2024.