Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "Industry Groupings, Not Seasonally Adjusted," in Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "April 1966," Federal Reserve Bulletin (April 1966) : 138-138. https://fraser.stlouisfed.org/title/62/item/21376/toc/297347 , accessed on April 19, 2024.