Columbia subject headings:
Harvard subject headings:
Avars--History--Congresses.
Europe, Central--Antiquities--Congresses.
Europe, Central--Civilization--Congresses.
Excavations (Archaeology)--Europe, Central--Congresses.
Lombards--History--Congresses.
Slavs--History--Congresses.
Social change--Europe, Central--History--Congresses.
Princeton subject headings:
Avars--History--Congresses.
Europe, Central--Antiquities--Congresses.
Europe, Central--Civilization--Congresses.
Lombards--History--Congresses.
Slavs--History--Congresses.
Social change--Europe, Central--Congresses.