Columbia subject headings:
Harvard subject headings:
Brochs.
Caithness (Scotland)--Antiquities.
Crosskirk Broch (Scotland)
Iron age--Scotland--Caithness.
Scotland--Antiquities.
Princeton subject headings:
Brochs.
Caithness (Scotland)--Antiquities.
Crosskirk Broch (Scotland)
Iron age--Scotland--Caithness (Highland Region).
Scotland--Antiquities.