Columbia subject headings:
Harvard subject headings:
Labor unions--Canada--Political activity--Congresses.
Labor unions--Political activity--Canada--Congresses.
Labor unions--Political activity--Congresses.
New Democratic Party--Congresses.
Socialist parties--Congresses.
Princeton subject headings:
Labor unions--Canada--Political activity--Congresses.
Labor unions--Political activity--Congresses.
New Democratic Party--Congresses.
Socialist parties--Congresses.