United States. Bureau of the Budget and United States. Office of Management and Budget. "Federal Sector of the National Income and Product Accounts," in United States. Bureau of the Budget and United States. Office of Management and Budget. "Fiscal Year 1969," Budget of the United States Government (January 29, 1968) : 543-543. https://fraser.stlouisfed.org/title/54/item/19022/toc/380794 , accessed on April 25, 2024.