Columbia subject headings:
Eastern question (Balkan)
Europe--History--1789-1900.
Europe--History--20th century.
Europe--Politics and government.
World War, 1914-1918--Causes.
Harvard subject headings:
Eastern question (Balkan)
Europe--History--1789-1900.
Europe--History--20th century.
World War, 1914-1918--Causes
Princeton subject headings: