Columbia subject headings:
Espionage, Communist--Germany.
Kommunistische Partei Deutschlands--History.
Kommunistische Partei Deutschlands. Nachrichtendienst.
Harvard subject headings:
Communism--Germany--History--20th century
Espionage, Communist--Germany.
Germany--Politics and government--1918-1933
Germany--Politics and government--1933-1945.
Kommunistische Partei Deutschlands--History.
Kommunistische Partei Deutschlands. Nachrichtendienst.
Princeton subject headings:
Communism--Germany--History--20th century.
Germany--Politics and government--1918-1933.
Germany--Politics and government--1933-1945.
Kommunistische Partei Deutschlands--History.