Board of Governors of the Federal Reserve System (U.S.), 1935-. "Treasury Currency and SDR Certificates, Unadjusted Net Flows," in Board of Governors of the Federal Reserve System (U.S.), 1935-. "May 19, 1981," Z.1 Financial Accounts of the United States (1981-05-19) : 35-35. https://fraser.stlouisfed.org/title/93/item/69129/toc/480883 , accessed on April 23, 2024.