United States. Department of the Treasury. "Press Package: Description Of Modified BTU Tax, April 1, 1993," in United States. Department of the Treasury. "Volume 321," Press Releases of the United States Department of the Treasury (March 1, 1993 - April 19, 1993) : 192-192. https://fraser.stlouisfed.org/title/6111/item/587164/toc/547160 , accessed on May 18, 2024.