Columbia subject headings:
Communism--Spain--History--20th century.
Partido Comunista de España--History.
Spain--History--20th century.
Harvard subject headings:
Communism--Spain--History--20th century
Partido Comunista de España--History.
Spain--History--20th century.
Princeton subject headings:
Communism--Spain--History--20th century.
Partido Comunista de España--History.
Spain--History--20th century.