United States. Department of the Treasury. "Revenue Act of 1928 Regulations, August 14, 1928," in United States. Department of the Treasury. "Volume 5," Press Releases of the United States Department of the Treasury (January 9, 1928 - December 20, 1928) : 192-193. https://fraser.stlouisfed.org/title/6111/item/586843/toc/557286 , accessed on March 28, 2024.