Schryen, GuidoGuidoSchryenWagner, GeritGeritWagner0000-0003-3926-7717Schlegel, AlexanderAlexanderSchlegel2022-10-172022-10-1720160167-4048https://fis.uni-bamberg.de/handle/uniba/55938engDevelopment of two novel face-recognition CAPTCHAs : A security and usability studyarticle10.1016/j.cose.2016.03.007http://www.scopus.com/inward/record.url?eid=2-s2.0-84973335052&partnerID=MN8TOARS