Board of Governors of the Federal Reserve System (U.S.), 1935-. "Diffusion Indexes," in Board of Governors of the Federal Reserve System (U.S.), 1935-. "June 15, 1989," G.12.3 Industrial Production (1989-06-15) : 15-15. https://fraser.stlouisfed.org/title/55/item/59749/toc/474558 , accessed on April 26, 2024.