United States. Bureau of Labor Statistics. "Contents," in United States. Bureau of Labor Statistics. "April 1978," PPI Detailed Report (April 1978) : 2-2. https://fraser.stlouisfed.org/title/63/item/21509/toc/189598 , accessed on July 11, 2024.
United States. Bureau of Labor Statistics. "Contents," in United States. Bureau of Labor Statistics. "April 1978," PPI Detailed Report (April 1978) : 2-2. https://fraser.stlouisfed.org/title/63/item/21509/toc/189598 , accessed on July 11, 2024.