United States. Bureau of Labor Statistics. "Technical Notes," in United States. Bureau of Labor Statistics. "May 1997," PPI Detailed Report (May 1997) : 206-210. https://fraser.stlouisfed.org/title/63/item/21740/toc/288539 , accessed on May 7, 2024.
United States. Bureau of Labor Statistics. "Technical Notes," in United States. Bureau of Labor Statistics. "May 1997," PPI Detailed Report (May 1997) : 206-210. https://fraser.stlouisfed.org/title/63/item/21740/toc/288539 , accessed on May 7, 2024.