Board of Governors of the Federal Reserve System (U.S.), 1935-. "Explanatory Note," in Board of Governors of the Federal Reserve System (U.S.), 1935-. "February 17, 1981," G.12.3 Industrial Production (1981-02-17) : 20-20. https://fraser.stlouisfed.org/title/55/item/59641/toc/472130 , accessed on March 28, 2024.