Columbia subject headings:
Harvard subject headings:
Christian biography--United States
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-
Walker, Laura, 1960-
Princeton subject headings:
Christian biography--United States.
Espionage--Soviet Union--History--20th century.
Espionage--United States--History--20th century.
Walker family.
Walker, John A., Jr. (John Anthony), 1937-2014.
Walker, Laura, 1960-