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-. "June 15, 1977," G.12.3 Industrial Production (1977-06-15) : 8-8. https://fraser.stlouisfed.org/title/55/item/59796/toc/470201 , accessed on April 23, 2024.