United States. Bureau of Labor Statistics. "Mining," in United States. Bureau of Labor Statistics. "April 1984," PPI Detailed Report (April 1984) : 143-143. https://fraser.stlouisfed.org/title/63/item/21581/toc/234086 , accessed on April 24, 2024.
United States. Bureau of Labor Statistics. "Mining," in United States. Bureau of Labor Statistics. "April 1984," PPI Detailed Report (April 1984) : 143-143. https://fraser.stlouisfed.org/title/63/item/21581/toc/234086 , accessed on April 24, 2024.