Occupational Outlook Handbook, 1966-67 Edition : Part 3 : Bulletin of the United States Bureau of Labor Statistics, No. 1450
United States. Bureau of Labor Statistics. "Occupational Outlook Handbook, 1966-67 Edition : Part 3 : Bulletin of the United States Bureau of Labor Statistics, No. 1450," Occupational Outlook Handbook (1965). https://fraser.stlouisfed.org/title/3964/item/498048/content/pdf/bls_1450_1965_3, accessed on April 19, 2024.