United States. Bureau of Labor Statistics. "Coal," in United States. Bureau of Labor Statistics. "November 1983," PPI Detailed Report (November 1983) : 13-13. https://fraser.stlouisfed.org/title/63/item/21576/toc/33179 , accessed on April 18, 2024.
United States. Bureau of Labor Statistics. "Coal," in United States. Bureau of Labor Statistics. "November 1983," PPI Detailed Report (November 1983) : 13-13. https://fraser.stlouisfed.org/title/63/item/21576/toc/33179 , accessed on April 18, 2024.