Hours and Earnings in Anthracite and Bituminous Coal Mining. Anthracite—January, 1922. Bituminous—Winter of 1921-22 : Bulletin of the United States Bureau of Labor Statistics, No. 316
United States. Bureau of Labor Statistics. "Hours and Earnings in Anthracite and Bituminous Coal Mining. Anthracite—January, 1922. Bituminous—Winter of 1921-22 : Bulletin of the United States Bureau of Labor Statistics, No. 316," Wages and Hours of Labor in Bituminous-Coal Mining (July 1922). https://fraser.stlouisfed.org/title/4021/item/493034, accessed on March 29, 2024.