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-. "April 15, 1983," G.12.3 Industrial Production (1983-04-15) : 14-14. https://fraser.stlouisfed.org/title/55/item/59666/toc/472573 , accessed on May 1, 2024.