Kaur, Harmanpreet, et al. “CrowdMask: Using Crowds to Preserve Privacy in Crowd-Powered Systems via Progressive Filtering”. Proceedings of the AAAI Conference on Human Computation and Crowdsourcing, vol. 5, no. 1, Sept. 2017, pp. 89-98, doi:10.1609/hcomp.v5i1.13314.