Columbia subject headings:
Harvard subject headings:
Heraldry--Germany--Rhineland.
Oidtman, Ernst von, 1854-1937--Archives.
Rhineland (Germany)--Genealogy.
Princeton subject headings:
Germany--Genealogy.
Heraldry--Germany.
Nobility--Germany--Genealogy.
Universitäts- und Stadtbibliothek Köln. Sammlung Ernst von Oidtman--Catalogs.