Gil de Gómez Pérez, David, and Roman Bednarik. “POnline: An Online Pupil Annotation Tool Employing Crowd-Sourcing and Engagement Mechanisms”. Human Computation 6, no. 1 (December 10, 2019): 176-191. Accessed June 8, 2025. http://104.237.144.41/index.php/jhc/article/view/99.