Perttula, Arttu, Kristian Kiili, Antero Lindstedt, and Pauliina Tuomi. “Flow Experience in Game Based Learning – a Systematic Literature Review”. International Journal of Serious Games 4, no. 1 (March 22, 2017). Accessed August 7, 2022. https://journal.seriousgamessociety.org/index.php/IJSG/article/view/151.