Columbia subject headings:
Communism--Europe--History--Sources.
Communist International--History--Sources.
Communist parties--Europe--History--Sources.
Harvard subject headings:
Communism--Europe--History--Sources.
Communist International--History--Sources.
Communist parties--Europe--History--Sources.
World War, 1939-1945--Cryptography.
World War, 1939-1945--France.
World War, 1939-1945--Germany.
World War, 1939-1945--Soviet Union.
Princeton subject headings:
Communism--Europe--History--Sources.
Communist International--History--Sources.
Communist parties--Europe--History--Sources.
World War, 1939-1945--Cryptography.
World War, 1939-1945--France.
World War, 1939-1945--Germany.
World War, 1939-1945--Soviet Union.