United States. Bureau of Labor Statistics. "Mining," in United States. Bureau of Labor Statistics. "May 1985," PPI Detailed Report (May 1985) : 163-163. https://fraser.stlouisfed.org/title/63/item/21594/toc/131639 , accessed on May 4, 2024.
United States. Bureau of Labor Statistics. "Mining," in United States. Bureau of Labor Statistics. "May 1985," PPI Detailed Report (May 1985) : 163-163. https://fraser.stlouisfed.org/title/63/item/21594/toc/131639 , accessed on May 4, 2024.