Columbia subject headings:
Harvard subject headings:
Archives--Germany--Bavaria--History--19th century.
Archives--Germany--Prussia--History--19th century.
Archives--History
History--Research
History--Sources
Princeton subject headings:
Archival resources--Access control--History--19th century.
Archives users--History--19th century.
Archives--Access control--History--19th century.
Archives--Research--History--19th century.