United States. Bureau of the Budget and United States. Office of Management and Budget. "Changes in Trust Fund Cash," in United States. Bureau of the Budget and United States. Office of Management and Budget. "Fiscal Year Ending June 30, 1963," Budget of the United States Government (January 18, 1962) : 277-277. https://fraser.stlouisfed.org/title/54/item/19016/toc/128023 , accessed on March 28, 2024.