Columbia subject headings:
Harvard subject headings:
Germany. Kriegsmarine--History--20th century.
Soviet Union--History--German occupation, 1941-1944.
World War, 1939-1945--Campaigns--Eastern Front.
World War, 1939-1945--Naval operations, German.
Princeton subject headings:
Germany. Kriegsmarine--History--World War, 1939-1945.
World War, 1939-1945--Campaigns--Baltic Sea.
World War, 1939-1945--Naval operations, German.