United States. Department of the Treasury. "First Annual Report of the Director of the Bureau of Statistics," in United States. Department of the Treasury. "Report of the Secretary of the Treasury on the State of the Finances for the Year 1867," Annual Report of the Secretary of the Treasury on the State of the Finances (1867) : 306-321. https://fraser.stlouisfed.org/title/194/item/5511/toc/329413 , accessed on April 20, 2024.