United States. Bureau of Labor Statistics. "Coal," in United States. Bureau of Labor Statistics. "November 1982," PPI Detailed Report (November 1982) : 14-14. https://fraser.stlouisfed.org/title/63/item/21564/toc/367709 , accessed on March 29, 2024.
United States. Bureau of Labor Statistics. "Coal," in United States. Bureau of Labor Statistics. "November 1982," PPI Detailed Report (November 1982) : 14-14. https://fraser.stlouisfed.org/title/63/item/21564/toc/367709 , accessed on March 29, 2024.