United States. Bureau of Labor Statistics. "Contents," in United States. Bureau of Labor Statistics. "May 1999," PPI Detailed Report (May 1999) : 3-4. https://fraser.stlouisfed.org/title/63/item/21764/toc/255531 , accessed on May 3, 2024.
United States. Bureau of Labor Statistics. "Contents," in United States. Bureau of Labor Statistics. "May 1999," PPI Detailed Report (May 1999) : 3-4. https://fraser.stlouisfed.org/title/63/item/21764/toc/255531 , accessed on May 3, 2024.