Knjige:

• Turing Tests: Captcha, Turing Test, Recaptcha, Reverse Turing Test, Minimum Intelligent Signal Test, Immortality Test by Books LLC
• Turing test: Turing test, CAPTCHA, Loebner Prize, Computing Machinery and Intelligence, Philosophy of artificial intelligence, Pathetic fallacy, Long Now Foundation by John McBrewster, Frederic P. Miller, and Agnes F. Vandome

Internet linkovi:

• http://en.wikipedia.org/wiki/CAPTCHA - Wikipedija o CAPTCHAi
• http://www.captcha.net/ - Oficijelna CAPTCHA stranica
• http://www.w3.org/TR/turingtest/ - Nedostupnost (fizički onesposobljenim osobama) CAPTCHA sistema