Columbia subject headings:
Bulgaria--Politics and government--1878-1944.
Political parties--Bulgaria--History--Sources.
Political parties--Bulgaria--History.
Harvard subject headings:
Bulgaria--Politics and government--1878-1944.
Political parties--Bulgaria--History.
Politicial parties--Bulgaria--History--Sources.
Princeton subject headings:
Bulgaria--Politics and government--1878-1944--Sources.
Political parties--Bulgaria--History--Sources.