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 15, 1964," G.12.3 Industrial Production (1964-04-15) : 1-1. https://fraser.stlouisfed.org/title/55/item/59526/toc/486187 , accessed on April 18, 2024.