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-. "May 15, 1973," G.12.3 Industrial Production (1973-05-15) : 7-7. https://fraser.stlouisfed.org/title/55/item/59775/toc/471416 , accessed on April 19, 2024.