Columbia subject headings:
Cologne (Germany)--Church history--19th century.
Cologne (Germany)--Church history--20th century.
Protestants--Germany--Cologne--History--19th century.
Protestants--Germany--Cologne--History--20th century.
Harvard subject headings:
Cologne (Germany)--Religious life and customs.
Protestant churches--Germany--Cologne--History.
Religious institutions--Germany--Cologne--History.
Princeton subject headings: