Columbia subject headings:
Krivitsky, W. G. (Walter G.), 1899-1941.
Soviet Union--Foreign relations--1917-1945.
Soviet Union. Obʺedinennoe gosudarstvennoe politicheskoe upravlenie--History.
Spies--Soviet Union--Biography.
Harvard subject headings:
Krivitsky, W. G. (Walter G.), 1899-1941.
Soviet Union--Foreign relations--1917-1945.
Soviet Union. Obʺedinennoe gosudarstvennoe politicheskoe upravlenie--History.
Spies--Soviet Union--Biography.
Princeton subject headings:
Krivitsky, W. G. (Walter G.), 1899-1941.
Soviet Union--Foreign relations--1917-1945.
Soviet Union. Obʺedinennoe gosudarstvennoe politicheskoe upravlenie--History.
Spies--Soviet Union--Biography.