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-. "February 15, 1989," G.12.3 Industrial Production (1989-02-15) : 14-14. https://fraser.stlouisfed.org/title/55/item/59745/toc/474497 , accessed on April 25, 2024.