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-. "March 13, 1987," G.12.3 Industrial Production (1987-03-13) : 14-14. https://fraser.stlouisfed.org/title/55/item/59717/toc/473772 , accessed on April 30, 2024.