Columbia subject headings:
Professions--Social aspects--Germany--History--19th century.
Professions--Social aspects--Germany--History--20th century.
Harvard subject headings:
Professions--Social aspects--Germany--History--19th century--Congresses.
Professions--Social aspects--Germany--History--20th century--Congresses.
Princeton subject headings:
Professions--Social aspects--Germany--History--19th century.
Professions--Social aspects--Germany--History--20th century.