Columbia subject headings:
Industrial relations--United States.
Labor unions--United States.
Labor unions.
Working class--United States.
Working class.
Harvard subject headings:
Industrial relations--United States
Labor and laboring classes--United States.
Labor unions
Labor unions--United States
Labor--United States
Working class
Working class--United States
Princeton subject headings:
Industrial relations--United States.
Labor unions.
Working class--United States.
Working class.