Columbia subject headings:
Harvard subject headings:
Labor unions--Political activity--Europe.
Labor unions--Political activity--Latin America.
Labor unions--Political activity--Middle East.
Working class--Political activity--Europe.
Working class--Political activity--Latin America.
Working class--Political activity--Middle East.
Princeton subject headings:
Labor unions--Political activity--Europe.
Labor unions--Political activity--Latin America.
Labor unions--Political activity--Middle East.
Working class--Political activity--Europe.
Working class--Political activity--Latin America.
Working class--Political activity--Middle East.