Columbia subject headings:
Labor journalism--Canada.
Labor journalism--United States.
Labor unions--Political activity--Canada.
Labor unions--Political activity--United States.
Harvard subject headings:
Labor journalism--Canada.
Labor journalism--United States.
Labor unions--Canada--Political activity.
Labor unions--United States--Political activity.
Princeton subject headings:
Labor journalism--Canada.
Labor journalism--United States.
Labor unions--Canada--Political activity.
Labor unions--United States--Political activity.