Columbia subject headings:
Espionage--Soviet Union--History--20th century.
Espionage--United States--History--20th century.
Walker family.
Walker, John A., Jr. (John Anthony), 1937-2014.
Whitworth, Jerry.
Harvard subject headings:
Espionage, Soviet--United States--History.
Espionage--Soviet Union--History--20th century.
Espionage--United States--History--20th century.
Walker family.
Walker, John A., Jr. (John Anthony), 1937-2014.
Walker, John Anthony, 1937-
Whitworth, Jerry, 1939-
Whitworth, Jerry.
Princeton subject headings:
Espionage--Soviet Union--History--20th century.
Espionage--United States--History--20th century.
Walker family.
Walker, John A., Jr. (John Anthony), 1937-2014.
Whitworth, Jerry.