Columbia subject headings:
Apses (Architecture)--Europe, Southern--Congresses.
Church architecture--Europe, Southern--History--Congresses.
Harvard subject headings:
Apses (Architecture)--Europe, Southern--Congresses.
Church architecture--Europe, Southern--History--Congresses.
Princeton subject headings:
Apses (Architecture)--Europe, Southern--Congresses.
Church architecture--Europe, Southern--History--Congresses.