Columbia subject headings:
Europe, Eastern--Foreign relations--European Union countries.
Europe, Southern--Foreign relations--European Union countries.
European Union countries--Foreign relations--Balkan Peninsula.
European Union countries--Foreign relations--Europe, Eastern.
European Union--Balkan Peninsula.
European Union--Europe, Eastern.
European federation.
Harvard subject headings:
Balkan Peninsula--Foreign relations--European Union countries.
Europe, Eastern--Foreign relations--European Union countries.
European Union countries--Foreign relations--Balkan Peninsula.
European Union countries--Foreign relations--Europe, Eastern.
European Union countries--Foreign relations--Europe, Southeastern.
European Union--Balkan Peninsula.
European Union--Europe, Eastern.
European Union--Europe, Southeastern.
European federation.
Princeton subject headings: