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-. "September 16, 1977," G.12.3 Industrial Production (1977-09-16) : 14-14. https://fraser.stlouisfed.org/title/55/item/59604/toc/470237 , accessed on March 29, 2024.