Board of Governors of the Federal Reserve System (U.S.), 1935-. "Industry Groupings, Seasonally Adjusted," in Board of Governors of the Federal Reserve System (U.S.), 1935-. "December 15, 1969," G.12.3 Industrial Production (1969-12-15) : 3-3. https://fraser.stlouisfed.org/title/55/item/59559/toc/492504 , accessed on April 19, 2024.