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. "March 1968," Federal Reserve Bulletin (March 1968) : 150-150. https://fraser.stlouisfed.org/title/62/item/21399/toc/5637 , accessed on May 11, 2024.