Columbia subject headings:
Catholic Church. Archdiocese of Cologne (Germany)--History--Sources.
Catholic Church. Diocese of Trier (Germany)--History--Sources.
Heraldry--Germany--North Rhine-Westphalia--Catalogs.
Seals (Numismatics)--Germany--Rhine Province.
Harvard subject headings:
Princeton subject headings:
Heraldry--Germany--North Rhine-Westphalia.
Heraldry--Germany--Rhineland-Palatinate.
Seals (Numismatics)--Germany--North Rhine-Westphalia--Catalogs.
Seals (Numismatics)--Germany--Rhineland-Palatinate--Catalogs.