Wei-Bin Lee, Che-Wei Fan, Kevin Ho, Chyi-Ren Dow. A CAPTCHA with Tips Related to Alphabets Upper or Lower Case. In 2012 Seventh International Conference on Broadband, Wireless Computing, Communication and Applications, Victoria, BC, Canada, November 12-14, 2012. pages 458-461, IEEE, 2012. [doi]
Abstract is missing.