Columbia subject headings:
Germany--History--Revolution, 1918.
Pomerania (Poland and Germany)--History--20th century.
Harvard subject headings:
Baltic Sea--History--20th century.
Germany--History--Revolution, 1918
Pomerania (Poland and Germany)--History--20th century.
World War, 1914-1918--Campaigns--Baltic Sea
Princeton subject headings:
Germany--History--Revolution, 1918.
Pomerania (Poland and Germany)--History--20th century.