Columbia subject headings:
Communist International.
Spain--History--Civil War, 1936-1939--Participation, Foreign.
Spain--History--Civil War, 1936-1939--Participation, Russian.
Harvard subject headings:
Communist International
Spain--History--Civil War, 1936-1939--Participation, Foreign.
Spain--History--Civil War, 1936-1939--Participation, Russian.
Princeton subject headings:
Communist International.
Spain--History--Civil War, 1936-1939--Foreign participation--Russian.
Spain--History--Civil War, 1936-1939--Foreign participation.