Mathisen, Gunnar E., idr. „Aerobic Games and Playful Exercises in 9-Year-Old Boys: Intensity and Fitness Effects“. Revija Za Elementarno izobraževanje, let. 9, št. 1/2, april 2016, str. 57-64, https://old.journals.um.si/index.php/education/article/view/374.