Columbia subject headings:
Labor laws and legislation--Spain.
Spain--History--Republic, 1931-1939.
Spain--Politics and government--1931-1939.
Vizcaya (Spain)--History.
Working class--Spain--Vizcaya--History--20th century.
Harvard subject headings:
Spain--Politics and government--1931-1939.
Vizcaya (Spain)--Politics and government.
Working class--Spain--Vizcaya--Political activity.
Princeton subject headings: