Columbia subject headings:
Opera--Germany--Hamburg--17th century.
Opera--Germany--Hamburg--18th century.
Opera--Political aspects--Germany--Hamburg.
Opera--Social aspects--Germany--Hamburg.
Harvard subject headings:
Opera--Germany--Hamburg--17th century.
Opera--Germany--Hamburg--18th century.
Opera--Political aspects--Germany--Hamburg.
Opera--Social aspects--Germany--Hamburg.
Princeton subject headings:
Opera--Germany--Hamburg--17th century.
Opera--Germany--Hamburg--18th century.
Opera--Political aspects--Germany--Hamburg.
Opera--Social aspects--Germany--Hamburg.