Columbia subject headings:
Excavations (Archaeology)--Bulgaria--Yantra River Watershed.
Prehistoric peoples--Bulgaria--Yantra River Watershed.
Yantra River Watershed (Bulgaria)--Antiquities.
Harvard subject headings:
Excavations (Archaeology)--Bulgaria--Yantra River Watershed.
Prehistoric peoples--Bulgaria--Yantra River Watershed.
Yantra River Watershed (Bulgaria)--Antiquities.
Princeton subject headings:
Antiquities, Prehistoric--Bulgaria.
Bulgaria--Antiquities.
Excavations (Archaeology)--Bulgaria--Yantra River Region.
Prehistoric peoples--Bulgaria--Yantra River Region.
Yantra River Region (Bulgaria)--Antiquities.
Yantra River Region (Bulgaria)--Civilization.