United States. Bureau of Labor Statistics. "Mining," in United States. Bureau of Labor Statistics. "August 1985," PPI Detailed Report (August 1985) : 177-177. https://fraser.stlouisfed.org/title/63/item/21597/toc/144434 , accessed on May 8, 2024.
United States. Bureau of Labor Statistics. "Mining," in United States. Bureau of Labor Statistics. "August 1985," PPI Detailed Report (August 1985) : 177-177. https://fraser.stlouisfed.org/title/63/item/21597/toc/144434 , accessed on May 8, 2024.