Board of Governors of the Federal Reserve System (U.S.), 1935-. "Seasonally Adjusted and Unadjusted Summary," in Board of Governors of the Federal Reserve System (U.S.), 1935-. "April 14, 1971," G.12.3 Industrial Production (1971-04-14) : 1-1. https://fraser.stlouisfed.org/title/55/item/59761/toc/468193 , accessed on March 29, 2024.