Columbia subject headings:
Anarchism--Spain--History--20th century.
Confederación Nacional del Trabajo (Spain)--History--20th century.
Syndicalism--Spain--History--20th century.
Harvard subject headings:
Anarchism--Spain--History--20th century
Confederación Nacional del Trabajo (Spain)--History--20th century.
Spain--Politics and government--1931-1939
Syndicalism--Spain--History--20th century.
Princeton subject headings: