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-. "April 14, 1972," G.12.3 Industrial Production (1972-04-14) : 2-2. https://fraser.stlouisfed.org/title/55/item/59739/toc/469918 , accessed on May 4, 2024.