Special Instructions to Collectors of Internal Revenue in the States of Arizona, California, Idaho, Nevada, Oregon, Utah and Washington, January 17, 1921
United States. Department of the Treasury. "Special Instructions to Collectors of Internal Revenue in the States of Arizona, California, Idaho, Nevada, Oregon, Utah and Washington, January 17, 1921," in United States. Department of the Treasury. "Volume 1A," Press Releases of the United States Department of the Treasury (March 30, 1918 - December 26, 1921) : 322-324. https://fraser.stlouisfed.org/title/6111/item/586836/toc/558029 , accessed on September 22, 2023.