United States. Bureau of Labor Statistics. "Mining," in United States. Bureau of Labor Statistics. "July 1984," PPI Detailed Report (July 1984) : 152-152. https://fraser.stlouisfed.org/title/63/item/21584/toc/373249 , accessed on April 19, 2024.
United States. Bureau of Labor Statistics. "Mining," in United States. Bureau of Labor Statistics. "July 1984," PPI Detailed Report (July 1984) : 152-152. https://fraser.stlouisfed.org/title/63/item/21584/toc/373249 , accessed on April 19, 2024.