Columbia subject headings:
Danube River Valley--Economic conditions.
Danube River Valley--Foreign economic relations.
Europe--Politics and government.
Great powers--History--20th century.
Harvard subject headings:
Danube River Valley--Economic conditions.
Danube River Valley--Foreign economic relations.
Europe--Politics and government--1918-1945.
Princeton subject headings:
Danube River Valley--Economic conditions.
Danube River Valley--Foreign economic relations.
Europe--Politics and government--1918-1945.
Great powers--History--20th century.