Elie Bursztein, Angelique Moscicki, Celine Fabry, Steven Bethard, John C. Mitchell, Dan Jurafsky. Easy does it: more usable CAPTCHAs. In Matt Jones, Philippe A. Palanque, Albrecht Schmidt, Tovi Grossman, editors, CHI Conference on Human Factors in Computing Systems, CHI'14, Toronto, ON, Canada - April 26 - May 01, 2014. pages 2637-2646, ACM, 2014. [doi]
Abstract is missing.