Columbia subject headings:
Harvard subject headings:
Anti-Nazi movement--Balkan Peninsula.
Anti-Nazi movement--Bulgaria.
World War, 1939-1945--Underground movements--Balkan Peninsula.
World War, 1939-1945--Underground movements--Bulgaria.
Princeton subject headings:
Anti-Nazi movement--Balkan Peninsula.
Anti-Nazi movement--Bulgaria.
World War, 1939-1945--Underground movements--Balkan Penisula.
World War, 1939-1945--Underground movements--Bulgaria.