United States. Bureau of Labor Statistics. "Contents," in United States. Bureau of Labor Statistics. "April 2006," PPI Detailed Report (April 2006) : 3-4. https://fraser.stlouisfed.org/title/63/item/21846/toc/285024 , accessed on March 28, 2024.
United States. Bureau of Labor Statistics. "Contents," in United States. Bureau of Labor Statistics. "April 2006," PPI Detailed Report (April 2006) : 3-4. https://fraser.stlouisfed.org/title/63/item/21846/toc/285024 , accessed on March 28, 2024.