Towards A Universally Usable Human Interaction Proof: Evaluation of Task Completion Strategies. - Graig Sauer; Jonathan Lazar; Harry Hochheiser; Jinjuan Feng (ACM Trans. Access. Comput., 2010)

Accessible privacy and security: a universally usable human-interaction proof tool. - Graig Sauer; Jonathan Holman; Jonathan Lazar; Harry Hochheiser; Jinjuan Feng (Univers. Access Inf. Soc., 2010)