Columbia subject headings:
Harvard subject headings:
Anarchism--Portugal--History--20th century.
Labor unions--Portugal--Political activity--History--20th century.
Portugal--Politics and government--1910-1974.
Syndicalism--Portugal--History--20th century.
Princeton subject headings:
Anarchism--Portugal--History--20th century.
Labor unions--Portugal--Political activity--History--20th century.
Portugal--Politics and government--1910-1974.
Syndicalism--Portugal--History--20th century.