Board of Governors of the Federal Reserve System (U.S.), 1935-. "Industry Groupings, Seasonally Adjusted," in Board of Governors of the Federal Reserve System (U.S.), 1935-. "April 15, 1976," G.12.3 Industrial Production (1976-04-15) : 4-4. https://fraser.stlouisfed.org/title/55/item/59589/toc/470061 , accessed on April 19, 2024.