United States. Bureau of Labor Statistics. "Employed and Unemployed Persons by Occupation, Not Seasonally Adjusted," in United States. Bureau of Labor Statistics. "August 2011," The Employment Situation (September 2, 2011) : 24-24. https://fraser.stlouisfed.org/title/144/item/494853/toc/507067 , accessed on April 23, 2024.