Columbia subject headings:
Middle class--Germany--History.
Nobility--Germany--History.
Harvard subject headings:
Elite (Social sciences)--Germany--History--19th century--Congresses.
Elite (Social sciences)--Germany--History--19th century.
Elite (Social sciences)--Germany--History--20th century.
Germany--Social conditions--19th century--Congresses.
Germany--Social conditions--19th century.
Germany--Social conditions--20th century.
Middle class--Germany--History--19th century--Congresses.
Middle class--Germany--History--19th century.
Middle class--Germany--History--20th century.
Nobility--Germany--History--19th century--Congresses.
Nobility--Germany--History--19th century.
Nobility--Germany--History--20th century.
Princeton subject headings:
Middle class--Germany--History--19th century.
Nobility--Germany--History--19th century.
Social classes--Germany--History--19th century.