Columbia subject headings:
Bulgaria--Foreign relations--Turkey.
Eastern question (Balkan)
Turkey--Foreign relations--Bulgaria.
Turkey--History--Tanzimat, 1839-1876.
Harvard subject headings:
Bulgaria--Foreign relations--Turkey.
Eastern question (Balkan).
Turkey--Foreign relations--Bulgaria.
Turkey--History--Tanzimat, 1839-1876.
Princeton subject headings:
Bulgaria--Foreign relations--Turkey.
Eastern question (Balkan)
Turkey--Foreign relations--Bulgaria.
Turkey--History--Tanzimat, 1839-1876.