Columbia subject headings:
Harvard subject headings:
Koblenz (Germany)--History--19th century.
Koblenz (Germany)--History--20th century.
Koblenz (Germany)--History--21st century.
Princeton subject headings:
Koblenz (Germany)--History--19th century.
Koblenz (Germany)--History--20th century.
Koblenz (Germany)--History--21st century.