Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "Indexes of Industrial Activity," in Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "May 1926," Federal Reserve Bulletin (May 1926) : 36-36. https://fraser.stlouisfed.org/title/62/item/20653/toc/384081 , accessed on March 28, 2024.