United States. Department of the Treasury. "Estimated Amount of Wholly Tax-Exempt Securities Outstanding, April 29, 1926," in United States. Department of the Treasury. "Volume 4A," Press Releases of the United States Department of the Treasury (January 4, 1926 - December 10, 1927) : 15-16. https://fraser.stlouisfed.org/title/6111/item/586842/toc/558067 , accessed on April 17, 2024.