Columbia subject headings:
Denmark--Church history.
Drang nach Osten.
Germany--Church history--843-1517.
Missions--Germany.
Missions--Poland.
Poland--Church history.
Harvard subject headings:
Denmark--Church history.
Drang nach Osten.
Germany--Church history--843-1517.
Missions--Germany.
Missions--Poland.
Poland--Church history
Princeton subject headings:
Denmark--Church history.
Drang nach Osten.
Germany--Church history--843-1517.
Missions--Germany.
Missions--Poland.
Poland--Church history.