Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "Net Ton-Miles, Revenue and Nonrevenue," in Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "December 1920," Federal Reserve Bulletin (December 1920) : 90-90. https://fraser.stlouisfed.org/title/62/item/20608/toc/344353 , accessed on March 28, 2024.