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-. "March 26, 1976," G.12.3 Industrial Production (1976-03-26) : 8-8. https://fraser.stlouisfed.org/title/55/item/59530/toc/470046 , accessed on April 23, 2024.