United States. Bureau of Labor Statistics. "Nondurable Manufacturing Sector," in United States. Bureau of Labor Statistics. "Preliminary Fourth-Quarter Measures and Annual Averages, 1998," Productivity and Costs (February 9, 1999) : 12-12. https://fraser.stlouisfed.org/title/131/item/55757/toc/437952 , accessed on May 8, 2024.