Board of Governors of the Federal Reserve System (U.S.), 1935-. "Market Groupings, Seasonally Adjusted and Unadjusted," in Board of Governors of the Federal Reserve System (U.S.), 1935-. "December 15, 1971," G.12.3 Industrial Production (1971-12-15) : 2-2. https://fraser.stlouisfed.org/title/55/item/59588/toc/468262 , accessed on April 19, 2024.