Kühnis, Jürgen, Beat Wachter, in Christian Frommelt. „Involvement in Sports Clubs and Informal Sport Activities of Primary and Secondary School Children in Liechtenstein“. Revija za elementarno izobraževanje 9, no. 1/2 (maj 15, 2016): 10 f. Pridobljeno september 24, 2025. https://old.journals.um.si/index.php/education/article/view/370.