Columbia subject headings:
Harvard subject headings:
Archives--Congresses
Diplomatics--History--Congresses.
Diplomatics--Study and teaching--Congresses.
Europe--History--Sources--Congresses.
History--Sources--Congresses.
Princeton subject headings:
Archives--Congresses.
Diplomatics--History--Congresses.
Diplomatics--Study and teaching--Congresses.
Europe--History--Sources--Congresses.
History--Sources--Congresses.