GRAD, Jan. “The Riddle of Play.” On Cognitive Difficulties in the Theoretical Approach of Play. Sensus Historiae, [S. l.], v. 54, n. 1, p. 95–109, 2024. DOI: 10.14746/sh.2024.54.1.007. Disponível em: https://pressto.amu.edu.pl/index.php/sh/article/view/53040. Acesso em: 14 apr. 2026.