Columbia subject headings:
Harvard subject headings:
Europe, Eastern--Boundaries--History.
Europe, Eastern--History.
Europe, Eastern--Politics and government.
Human geography--Europe, Eastern--History.
Political geography.
Space perception--Political aspects--Europe, Eastern.
Space perception--Social aspects--Europe, Eastern.
Princeton subject headings:
Europe, Eastern--Boundaries--History.
Europe, Eastern--History.
Europe, Eastern--Politics and government.
Human geography--Europe, Eastern--History.
Political geography.
Space perception--Political aspects--Europe, Eastern.
Space perception--Social aspects--Europe, Eastern.