Columbia subject headings:
Balkan Peninsula--Foreign relations--Russia--Congresses.
Russia--Foreign relations--1801-1917--Congresses.
Russia--Foreign relations--Balkan Peninsula--Congresses.
Harvard subject headings:
Balkan Peninsula--Foreign relations--Russia--Congresses.
Russia--Foreign relations--1801-1917--Congresses.
Russia--Foreign relations--Balkan Peninsula--Congresses.
Princeton subject headings:
Balkan Peninsula--Foreign relations--Russia--Congresses.
Russia--Foreign relations--1801-1917--Congresses.
Russia--Foreign relations--Balkan Peninsula--Congresses.