Columbia subject headings:
Harvard subject headings:
Balkan Peninsula--Politics and government.
European Union--Balkan Peninsula.
International law--Balkan Peninsula.
National security--Balkan Peninsula
Princeton subject headings:
Balkan Peninsula--Foreign relations--European Union countries.
Balkan Peninsula--Foreign relations--United States.
Balkan Peninsula--Politics and government.
European Union countries--Foreign relations--Balkan Peninsula.
International law--Balkan Peninsula.
United States--Foreign relations--Balkan Peninsula.