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-. "July 14, 1989," G.12.3 Industrial Production (1989-07-14) : 14-14. https://fraser.stlouisfed.org/title/55/item/59750/toc/474581 , accessed on April 19, 2024.