Columbia subject headings:
Bulgaria--Foreign relations--Russia.
Bulgaria--History--1762-1878.
Eastern question (Balkan)
Russia--Foreign relations--Bulgaria.
Russia--History--Alexander II, 1855-1881.
Russo-Turkish War, 1877-1878.
Harvard subject headings:
Bulgaria--Foreign relations--Russia.
Bulgaria--History--1762-1878.
Eastern question (Balkan)
Russia--Foreign relations--Bulgaria.
Russia--History--Alexander II, 1855-1881.
Russo-Turkish War, 1877-1878.
Princeton subject headings:
Balkan Peninsula--History--19th century--Congresses.
Bulgaria--History--1762-1878--Congresses.
Eastern question (Balkan)--History--19th century--Congresses.
Russia--History--Alexander II, 1855-1881--Congresses.
Russo-Turkish War, 1877-1878--History--Congresses.