Columbia subject headings:
Foreign workers--United States--History.
Labor unions--Political activity--United States.
United States--Emigration and immigration--History.
Harvard subject headings:
Foreign workers--United States--History.
Labor unions--Political activity--United States.
Labor unions--United States--Political activity.
United States--Emigration and immigration--History.
Princeton subject headings:
Foreign workers--United States--History.
Labor unions--United States--Political activity.
United States--Emigration and immigration--History.