United States. Bureau of the Budget and United States. Office of Management and Budget. "Explanatory Note Relating to the Summary Tables," in United States. Bureau of the Budget and United States. Office of Management and Budget. "Fiscal Year 1972," Budget of the United States Government (January 29, 1971) : 517-517. https://fraser.stlouisfed.org/title/54/item/19026/toc/60551 , accessed on May 7, 2024.