APA Citation

Pakdel, R. (2012). A user-friendly CAPTCHA scheme based on usability features.

Chicago Style Citation

Pakdel, Rezvan. A User-friendly CAPTCHA Scheme Based On Usability Features. 2012.

MLA Citation

Pakdel, Rezvan. A User-friendly CAPTCHA Scheme Based On Usability Features. 2012.

Warning: These citations may not always be 100% accurate.