United States. Bureau of Labor Statistics. "Mining," in United States. Bureau of Labor Statistics. "April 1983," PPI Detailed Report (April 1983) : 123-123. https://fraser.stlouisfed.org/title/63/item/21569/toc/422060 , accessed on April 25, 2024.
United States. Bureau of Labor Statistics. "Mining," in United States. Bureau of Labor Statistics. "April 1983," PPI Detailed Report (April 1983) : 123-123. https://fraser.stlouisfed.org/title/63/item/21569/toc/422060 , accessed on April 25, 2024.