Steven A. Ross, J. Alex Halderman, Adam Finkelstein. Sketcha: a captcha based on line drawings of 3D models. In Michael Rappa, Paul Jones, Juliana Freire, Soumen Chakrabarti, editors, Proceedings of the 19th International Conference on World Wide Web, WWW 2010, Raleigh, North Carolina, USA, April 26-30, 2010. pages 821-830, ACM, 2010. [doi]
Abstract is missing.