Columbia subject headings:
Europe--Foreign relations--Spain.
Soviet Union--Relations--Spain.
Spain--Foreign relations--Europe.
Spain--History--Civil War, 1936-1939--Causes.
Spain--Politics and government--1931-1939.
Spain--Relations--Soviet Union.
Harvard subject headings:
Spain--History--Civil War, 1936-1939.
Spain--History--Republic, 1931-1939.
Spain--Politics and government--1931-1939.
Princeton subject headings:
Europe--Foreign relations--Spain.
Soviet Union--Relations--Spain.
Spain--Foreign relations--Europe.
Spain--History--Civil War, 1936-1939--Causes.
Spain--Politics and government--1931-1939.
Spain--Relations--Soviet Union.