Board of Governors of the Federal Reserve System (U.S.), 1935-. "Industry Groupings, Not Seasonally Adjusted," in Board of Governors of the Federal Reserve System (U.S.), 1935-. "1987 Revision," G.12.3 Industrial Production (1987-01-01) : 15-16. https://fraser.stlouisfed.org/title/55/item/59714/toc/492581 , accessed on May 2, 2024.