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-. "September 13, 1974," G.12.3 Industrial Production (1974-09-13) : 4-4. https://fraser.stlouisfed.org/title/55/item/59798/toc/471552 , accessed on April 25, 2024.