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 16, 1972," G.12.3 Industrial Production (1972-05-16) : 8-8. https://fraser.stlouisfed.org/title/55/item/59593/toc/469926 , accessed on March 28, 2024.