Columbia subject headings:
Harvard subject headings:
Ellis, Charles Howard, 1895-
Espionage--Great Britain--History--20th century.
Gouzenko, Igor, 1919-1982.
Spies--Great Britain--Biography.
Stephenson, William Samuel, 1896-1989.
Princeton subject headings:
Espionage--Great Britain--History--20th century.
Spies--Great Britain--Biography.
Stephenson, William Samuel, 1896-1989.