Columbia subject headings:
Harvard subject headings:
Ostfriesland (Germany)--History--20th century--Exhibitions.
Ostfriesland (Germany)--History--20th century.
World War, 1914-1918--Germany--Ostfriesland.
Princeton subject headings:
Ostfriesland (Germany)--History--20th century--Exhibitions.
Ostfriesland (Germany)--History--20th century.
World War, 1914-1918--Germany--Ostfriesland.