United States. Bureau of Labor Statistics. "Employed and Unemployed Persons by Occupation, Not Seasonally Adjusted," in United States. Bureau of Labor Statistics. "November 2007," The Employment Situation (December 7, 2007) : 19-19. https://fraser.stlouisfed.org/title/144/item/494808/toc/508238 , accessed on April 25, 2024.