United States. Bureau of Labor Statistics. "Tomorrow's Manpower Needs, Vol. IV Revised 1971: The National Industry-Occupational Matrix and Other Manpower Data : Bulletin of the United States Bureau of Labor Statistics, No. 1737" in Tomorrow's Manpower Needs: National Manpower Projections and a Guide to Their Use as a Tool in Developing State and Area Manpower Projections : Bulletin of the United States Bureau of Labor Statistics, No. 1606 (1972). https://fraser.stlouisfed.org/title/4863/item/498879, accessed on March 22, 2025.