Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "Industry and Summary Market Groupings, Seasonally Adjusted," in Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "April 1961," Federal Reserve Bulletin (April 1961) : 70-70. https://fraser.stlouisfed.org/title/62/item/21316/toc/141846 , accessed on March 29, 2024.