Columbia subject headings:
Harvard subject headings:
Europe, Central--History--Congresses.
Europe, Central--Social conditions--Congresses.
Europe, German-speaking--History--Congresses.
Europe, German-speaking--Social conditions--Congresses.
Princeton subject headings:
Europe, Central--History--Congresses.
Europe, Central--Social conditions--Congresses.
Europe, German-speaking--History--Congresses.
Europe, German-speaking--Social conditions--Congresses.