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-. "September 14, 1988," G.12.3 Industrial Production (1988-09-14) : 6-6. https://fraser.stlouisfed.org/title/55/item/59740/toc/474398 , accessed on March 28, 2024.