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-. "May 16, 1988," G.12.3 Industrial Production (1988-05-16) : 15-15. https://fraser.stlouisfed.org/title/55/item/59734/toc/474325 , accessed on April 19, 2024.