Extra Credit as a Spaced-Study Motivator. International Journal on Studies in Education, [S. l.], v. 5, n. 4, p. 496–514, 2023. DOI: 10.46328/ijonse.166. Disponível em: https://ijonse.net/index.php/ijonse/article/view/1860. Acesso em: 25 jul. 2025.