Columbia subject headings:
Bulgaria--Social life and customs.
Folklore--Thrace.
Mumming--Bulgaria.
New Year--Bulgaria.
Thrace--Social life and customs.
Harvard subject headings:
Christmas--Bulgaria.
Folklore--Bulgaria
Mumming--Bulgaria.
Princeton subject headings:
Bulgaria--Social life and customs.
Folklore--Thrace.
Mumming--Bulgaria.
New Year--Bulgaria.
Thrace--Social life and customs.