Columbia subject headings:
Anarchism--Spain--History--20th century.
Anarchists--Spain--History--20th century.
Labor unions--Political activity--Spain--History--20th century.
Spain--History--Civil War, 1936-1939.
Spain--Politics and government--1931-1939.
Harvard subject headings:
Anarchism--Spain--History--20th century
Anarchists--Spain--History--20th century.
Labor unions--Political activity--Spain--History--20th century.
Labor unions--Spain--Political activity--History--20th century.
Spain--History--Civil War, 1936-1939.
Spain--Politics and government--1931-1939.
Princeton subject headings:
Anarchism--Spain--History--20th century.
Anarchists--Spain--History--20th century.
Labor unions--Spain--Political activity--History--20th century.
Spain--History--Civil War, 1936-1939.
Spain--Politics and government--1931-1939.