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-. "April 14, 1989," G.12.3 Industrial Production (1989-04-14) : 6-6. https://fraser.stlouisfed.org/title/55/item/59747/toc/474529 , accessed on March 29, 2024.