Mathisen, G.E., Jensen, R.M. and Pettersen, S.A. (2016) “Aerobic Games and Playful exercises in 9-Year-Old Boys: Intensity and Fitness Effects”, Journal of Elementary Education, 9(1/2), pp. 57–64. Available at: https://old.journals.um.si/index.php/education/article/view/374 (Accessed: 8 November 2025).