Columbia subject headings:
Harvard subject headings:
Bolu İli (Turkey)--Census--History.
Bolu İli (Turkey)--History.
Bolu İli (Turkey)--Population--History--19th century.
Princeton subject headings:
Bolu İli (Turkey)--Census--History.
Bolu İli (Turkey)--History.
Bolu İli (Turkey)--Population--History--19th century.