United States. Bureau of Labor Statistics. "Full- and Part-Time Status of the Civilian Labor Force," in United States. Bureau of Labor Statistics. "December 1973 : Industry Statistics and Annual Review," The Employment Situation (January 11, 1974) : 11-11. https://fraser.stlouisfed.org/title/144/item/497002/toc/512645 , accessed on April 19, 2024.