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-. "October 18, 1971," G.12.3 Industrial Production (1971-10-18) : 8-8. https://fraser.stlouisfed.org/title/55/item/59586/toc/468235 , accessed on April 19, 2024.