United States. Bureau of Labor Statistics. "Mining," in United States. Bureau of Labor Statistics. "January 1983," PPI Detailed Report (January 1983) : 128-128. https://fraser.stlouisfed.org/title/63/item/21566/toc/317291 , accessed on May 4, 2024.
United States. Bureau of Labor Statistics. "Mining," in United States. Bureau of Labor Statistics. "January 1983," PPI Detailed Report (January 1983) : 128-128. https://fraser.stlouisfed.org/title/63/item/21566/toc/317291 , accessed on May 4, 2024.