United States. Bureau of Labor Statistics. "Manufacturing Sector - Appendix - Quarterly Data," in United States. Bureau of Labor Statistics. "Third Quarter 1998 [Revised]," Productivity and Costs (December 3, 1998) : 13-13. https://fraser.stlouisfed.org/title/131/item/55756/toc/437469 , accessed on May 2, 2024.