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-. "May 15, 1974," G.12.3 Industrial Production (1974-05-15) : 8-8. https://fraser.stlouisfed.org/title/55/item/59537/toc/471520 , accessed on April 19, 2024.