Columbia subject headings:
Harvard subject headings:
Germany--History, Naval--20th century
Germany--Military policy
Germany. Kriegsmarine--History--20th century.
Germany. Reichsmarine--History--20th century.
Princeton subject headings:
Germany--History, Naval--20th century.
Germany--Military policy.
Germany. Kriegsmarine--History--20th century.
Germany. Reichsmarine--History--20th century.