Columbia subject headings:
Bulgaria--History--1762-1878.
Bulgaria--Relations--Romania.
Bulgarians--Romania--History.
Romania--Relations--Bulgaria.
Harvard subject headings:
Bulgaria--History--1762-1878.
Bulgaria--Relations--Romania.
Bulgarians--Romania--History.
Romania--Relations--Bulgaria.
Princeton subject headings:
Bulgaria--History--1762-1878.
Bulgaria--Relations--Romania.
Bulgarians--Romania--History.
Romania--Relations--Bulgaria.