United States. Bureau of Labor Statistics. "Charts," in United States. Bureau of Labor Statistics. "April 1999," PPI Detailed Report (April 1999) : 8-10. https://fraser.stlouisfed.org/title/63/item/21763/toc/231548 , accessed on April 25, 2024.
United States. Bureau of Labor Statistics. "Charts," in United States. Bureau of Labor Statistics. "April 1999," PPI Detailed Report (April 1999) : 8-10. https://fraser.stlouisfed.org/title/63/item/21763/toc/231548 , accessed on April 25, 2024.