Columbia subject headings:
Harvard subject headings:
Balkan Peninsula--History--Congresses.
Christian antiquities--Balkan Peninsula--Congresses.
Church history--Primitive and early church, ca. 30-600--Congresses.
Princeton subject headings:
Balkan Peninsula--History--Congresses.
Christian antiquities--Balkan Peninsula--Congresses.
Church history--Primitive and early church, ca. 30-600--Congresses.