United States. Bureau of Labor Statistics. "Contents," in United States. Bureau of Labor Statistics. "April 2009," PPI Detailed Report (April 2009) : 2-3. https://fraser.stlouisfed.org/title/63/item/21883/toc/222593 , accessed on April 26, 2024.
United States. Bureau of Labor Statistics. "Contents," in United States. Bureau of Labor Statistics. "April 2009," PPI Detailed Report (April 2009) : 2-3. https://fraser.stlouisfed.org/title/63/item/21883/toc/222593 , accessed on April 26, 2024.