Board of Governors of the Federal Reserve System (U.S.), 1935-. "Market Groupings, Seasonally Adjusted," in Board of Governors of the Federal Reserve System (U.S.), 1935-. "April 14, 1977," G.12.3 Industrial Production (1977-04-14) : 3-3. https://fraser.stlouisfed.org/title/55/item/59519/toc/470184 , accessed on April 23, 2024.