Columbia subject headings:
Harvard subject headings:
Labor movement--Portugal--History--20th century.
Labor unions--Portugal--History--20th century.
Portugal--Politics and government--1974-
Portugal--Social conditions--20th century.
Princeton subject headings:
Labor movement--Portugal--History--20th century.
Labor unions--Portugal--History--20th century.
Portugal--Politics and government--1974-
Portugal--Social conditions--20th century.