Board of Governors of the Federal Reserve System (U.S.), 1935-. "Industry Groupings, Not Seasonally Adjusted," in Board of Governors of the Federal Reserve System (U.S.), 1935-. "May 14, 1971," G.12.3 Industrial Production (1971-05-14) : 5-5. https://fraser.stlouisfed.org/title/55/item/59645/toc/468204 , accessed on April 18, 2024.