Donn Morrison, Stéphane Marchand-Maillet, Eric Bruno. TagCaptcha: annotating images with CAPTCHAs. In Paul N. Bennett, Raman Chandrasekar, Max Chickering, Panagiotis G. Ipeirotis, Edith Law, Anton Mityagin, Foster J. Provost, Luis von Ahn, editors, Proceedings of the ACM SIGKDD Workshop on Human Computation, Paris, France, June 28, 2009. pages 44-45, ACM, 2009. [doi]
Abstract is missing.