United States. Bureau of Labor Statistics. "Unemployed Persons by Reason for Unemployment, Sex, Age, and Color," in United States. Bureau of Labor Statistics. "April 1970," The Employment Situation (May 8, 1970) : 10-10. https://fraser.stlouisfed.org/title/144/item/496959/toc/513078 , accessed on April 30, 2024.