United States. Bureau of the Budget and United States. Office of Management and Budget. "Explanation of Principles Used in Compiling Tables," in United States. Bureau of the Budget and United States. Office of Management and Budget. "Fiscal Year 1970," Budget of the United States Government (January 15, 1969) : 479-481. https://fraser.stlouisfed.org/title/54/item/19024/toc/237702 , accessed on April 23, 2024.