Columbia subject headings:
Harvard subject headings:
Danube River Region--Intellectual life.
Danube River Region--Relations.
Danube River Region--Social conditions.
Danube River Region--Study and teaching.
Danube River Valley--Civilization.
Danube River Valley--Description and travel.
Danube River Valley--History, Local.
Danube River Valley--History.
Danube River--Description and travel.
Danube River--History.
Geopolitics--Danube River Valley.
Intercultural communication--Danube River Region.
Politics and culture--Danube River Region.
Politics and literature--Danube River Region.
Regionalism--Danube River Region.
Princeton subject headings:
Danube River Valley--Civilization.
Danube River Valley--Description and travel.
Danube River Valley--History, Local.
Danube River Valley--History.
Danube River--Description and travel.
Danube River--History.
Geopolitics--Danube River Valley.