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-. "December 15, 1976," G.12.3 Industrial Production (1976-12-15) : 4-4. https://fraser.stlouisfed.org/title/55/item/59520/toc/470140 , accessed on March 29, 2024.