SA, 2009 https://www.nsa.gov/about/cryptologic_heritage/center_crypt_history/pearl_ha rbor_review/black_chamber.shtml “Tts sensitive ears catch ,,,’—David Kahn, 7he Codebreakers (Simon and Schuster, New York), 1967 p.358 “Expeditions to penetrate cables...”—Bob Woodward, Veil: The Secret Wars of the CIA, 19