Board of Governors of the Federal Reserve System (U.S.), 1935-. "Summary Groupings, Seasonally Adjusted," in Board of Governors of the Federal Reserve System (U.S.), 1935-. "December 14, 1973," G.12.3 Industrial Production (1973-12-14) : 8-8. https://fraser.stlouisfed.org/title/55/item/59536/toc/471473 , accessed on April 25, 2024.