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-. "December 14, 1988," G.12.3 Industrial Production (1988-12-14) : 14-14. https://fraser.stlouisfed.org/title/55/item/59743/toc/474448 , accessed on April 18, 2024.