Columbia subject headings:
Balkan Peninsula--Defenses.
Balkan Peninsula--Foreign relations--1989-
Balkan Peninsula--Politics and government.
National security--Balkan Peninsula.
Harvard subject headings:
Balkan Peninsula--Defenses.
Balkan Peninsula--Foreign relations--1989-
Balkan Peninsula--Politics and government.
National security--Balkan Peninsula
Princeton subject headings:
Balkan Peninsula--Defenses.
Balkan Peninsula--Foreign relations--1989-
Balkan Peninsula--Politics and government.
National security--Balkan Peninsula.