1. 2008. ZDNet - Inside India's CAPTCHA solving economy. (2008). http://www.zdnet.com/article/inside-indias-captcha-solving-economy/. 2008. ZDNet - Inside India's CAPTCHA solving economy. (2008). http://www.zdnet.com/article/inside-indias-captcha-solving-economy/.
2. 2012. David Pogue - Time to Kill Off Captchas. (2012). https://www.scientificamerican.com/article/time-to-kill-off-captchas/. 2012. David Pogue - Time to Kill Off Captchas. (2012). https://www.scientificamerican.com/article/time-to-kill-off-captchas/.
3. 2014. PopTech - Luis von Ahn: CAPTCHAs' My fault.. (2014). https://poptech.org/blog/luis_von_ahn_captchas_my_fault. 2014. PopTech - Luis von Ahn: CAPTCHAs' My fault.. (2014). https://poptech.org/blog/luis_von_ahn_captchas_my_fault.
4. 2014. World Health Organization - Visual Impairment and Blindness. (2014). http://www.who.int/mediacentre/factsheets/fs282/en/. 2014. World Health Organization - Visual Impairment and Blindness. (2014). http://www.who.int/mediacentre/factsheets/fs282/en/.
5. 2017. Reaching new records in speech recognition. (2017). https://www.ibm.com/blogs/watson/2017/03/reaching-new-records-in-speech-recognition/. 2017. Reaching new records in speech recognition. (2017). https://www.ibm.com/blogs/watson/2017/03/reaching-new-records-in-speech-recognition/.