Columbia subject headings:
Harvard subject headings:
Germany--Relations--Poland
Poland--History--German occupation, 1914-1918
Poland--Relations--Germany
World War, 1914-1918--Diplomatic history
World War, 1914-1918--Poland
World War, 1914-1918--Religious aspects--Catholic Church
Princeton subject headings:
Catholic Church.
German government
Poland--20th century.
World War, 1914-1918--Poland.