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-. "April 16, 1973," G.12.3 Industrial Production (1973-04-16) : 7-7. https://fraser.stlouisfed.org/title/55/item/59544/toc/471408 , accessed on March 28, 2024.