Columbia subject headings:
Harvard subject headings:
Cologne (Germany)--Biography.
Cologne (Germany)--History--Bombardment, 1939-1945.
Pettenberg, Heinz--Diaries.
World War, 1939-1945--Personal narratives, German.
Princeton subject headings:
Cologne (Germany)--Biography.
Cologne (Germany)--History--Bombardment, 1939-1945.
Pettenberg, Heinz--Diaries.
World War, 1939-1945--Personal narratives, German.