Columbia subject headings:
Harvard subject headings:
Europe--Genealogy--Congresses.
Germany--Genealogy--Congresses.
Nobility--Europe--Genealogy--Congresses.
Nobility--Europe--History--Congresses.
Nobility--Genealogy--Congresses.
Social status--Europe--History--Congresses.
Princeton subject headings:
Europe--Genealogy--Congresses.
Germany--Genealogy--Congresses.
Nobility--Genealogy--Congresses.
Social status--Europe--History--Congresses.