How Codebreaker Elizebeth Friedman Broke Up a Nazi Spy RingFebruary 9, 2021https://www.smithsonianmag.com/smart-news/new-pbs-film-tells-story-wwii-codebreaker-elizabeth-friedman-180976759/ Codebreaker https://www.pbs.org/wgbh/americanexperience/films/codebreaker/