Columbia subject headings:
Harvard subject headings:
Archives--Access control--Germany--Congresses
Archives--Law and legislation--Germany--Congresses.
Restricted collections in archives--Germany--Congresses.
Security classification (Government documents)--Germany--Congresses.
Princeton subject headings:
Archives--Access control--Germany--Congresses.
History--Research--Congresses.
Restricted collections in archives--Germany--Congresses.