Columbia subject headings:
Harvard subject headings:
Cryptography--United States--History--Sources.
Espionage, Soviet--United States--History--Sources.
Sokolov, Vladimir--History--Sources.
Soviet Union--Foreign relations--United States--Sources.
Soviet Union. Glavnoe razvedyvatelʹnoe upravlenie--History--Sources.
Soviet Union. Komitet gosudarstvennoĭ bezopasnosti--History--Sources.
United States--Foreign relations--Soviet Union--Sources.
United States. Signal Security Agency--History--Sources.
Princeton subject headings:
Cryptography--United States--History--Sources.
Espionage, Soviet--United States--History--Sources.
Soviet Union--Foreign relations--United States--History--Sources.
Soviet Union. Glavnoe razvedyvatelʹnoe upravlenie--History--Sources.
Soviet Union. Komitet gosudarstvennoĭ bezopasnosti--History--Sources.
United States--Foreign relations--Soviet Union--History--Sources.
United States. Signal Security Agency--History--Sources.