POnline: An Online Pupil Annotation Tool Employing Crowd-sourcing and Engagement Mechanisms. Human Computation, [S. l.], v. 6, n. 1, p. 176–191, 2019. DOI: 10.15346/hc.v6i1.9. Disponível em: http://www.hcjournal.org/index.php/jhc/article/view/99. Acesso em: 24 feb. 2026.