Columbia subject headings:
País Vasco (Spain)--Politics and government--20th century.
Socialism--Spain--País Vasco--History--20th century.
Socialists--Spain--País Vasco--History--20th century.
Harvard subject headings:
País Vasco (Spain)--Politics and government
Partido Socialista de Euskadi--History.
Socialism--Spain--País Vasco--History.
Socialists--Spain--País Vasco.
Princeton subject headings:
País Vasco (Spain)--Politics and government.
Partido Socialista de Euskadi--History.
Socialism--Spain--País Vasco--History.
Socialists--Spain--País Vasco.