United States. Bureau of Labor Statistics. "Contents," in United States. Bureau of Labor Statistics. "May 1988," PPI Detailed Report (May 1988) : 3-3. https://fraser.stlouisfed.org/title/63/item/21630/toc/151342 , accessed on April 18, 2024.
United States. Bureau of Labor Statistics. "Contents," in United States. Bureau of Labor Statistics. "May 1988," PPI Detailed Report (May 1988) : 3-3. https://fraser.stlouisfed.org/title/63/item/21630/toc/151342 , accessed on April 18, 2024.