Columbia subject headings:
Anarchists--Spain--Biography.
Balius, Jaime.
Durruti, Buenaventura, 1896-1936.
Spain--History--Civil War, 1936-1939.
Harvard subject headings:
Amigos de Durruti.
Anarchists--Spain--History--20th century.
Balius, Santiago María, 1904-1980.
Labor unions and communism--Spain--History--20th century.
Princeton subject headings: