Brunner, Esther, Hedwig Gasteiger, Jonas Lampart, and Kathrin Schreieder. “Mathematics in Age-Mixed Classes in Swiss and in German Primary Schools: A Comparative Study”. Swiss Journal of Educational Research 41, no. 1 (April 3, 2019): 160–176. Accessed December 4, 2024. https://sjer.ch/article/view/5447.