Columbia subject headings:
World War, 1939-1945--Naval operations--Submarine.
World War, 1939-1945--Personal narratives, German.
Harvard subject headings:
World War, 1939-1945--Personal narratives, German.
Princeton subject headings:
World War, 1939-1945--Naval operations--Submarine.
World War, 1939-1945--Personal narratives, German.