Pakdel, R. (2012). A user-friendly CAPTCHA scheme based on usability features.
Chicago Style CitationPakdel, Rezvan. A User-friendly CAPTCHA Scheme Based On Usability Features. 2012.
MLA CitationPakdel, Rezvan. A User-friendly CAPTCHA Scheme Based On Usability Features. 2012.
Warning: These citations may not always be 100% accurate.