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