Columbia subject headings:
Brochs--Scotland.
Fortification, Prehistoric--Scotland.
Scotland--Antiquities.
Harvard subject headings:
Brochs--Scotland.
Excavations (Archaeology)--Scotland
Fortification, Prehistoric--Scotland.
Iron age--Scotland
Scotland--Antiquities.
Princeton subject headings:
Brochs--Scotland.
Fortification, Prehistoric--Scotland.
Scotland--Antiquities.