Columbia subject headings:
Labor unions--Political activity--Spain--History--20th century.
Socialism--Spain.
Strikes and lockouts--Spain.
Harvard subject headings:
Labor unions--Political activity--Spain--History--20th century.
Labor unions--Spain--Political activity--History--20th century.
Socialism--Spain
Strikes and lockouts--Spain
Princeton subject headings:
Labor unions--Spain--Political activity.
Spain--Politics and government--1975-.
Spain--Social conditions--1975-
Unión General de Trabajadores de España.