Board of Governors of the Federal Reserve System (U.S.), 1935-. "Gross public debt of the U.S. Treasury-Types and ownership," in Board of Governors of the Federal Reserve System (U.S.), 1935-. "1990," Annual Statistical Digest (November 1991) : 56-56. https://fraser.stlouisfed.org/title/7/item/23496/toc/252099 , accessed on April 19, 2024.