Columbia subject headings:
Harvard subject headings:
Air pilots, Military
Neutrality--Switzerland--History--20th century.
Prisoners of war--Switzerland.
World War, 1939-1945--Aerial operations, Swiss.
World War, 1939-1945--Antiaircraft artillery operations, Swiss.
World War, 1939-1945--Switzerland.
Princeton subject headings:
Neutrality--Switzerland.
World War, 1939-1945--Switzerland--Aerial operations.
World War, 1939-1945--Switzerland--Antiaircraft artillery operations.