Mining
United States. Bureau of Labor Statistics. "Mining," in United States. Bureau of Labor Statistics. "Employment, Hours, and Earnings, United States, 1988-96 : Bulletin of the United States Bureau of Labor Statistics, No. 2481," Employment and Earnings, United States (August 1996) : 14-21. https://fraser.stlouisfed.org/title/189/item/5439/toc/123448 , accessed on May 1, 2024.