Słomczyńska, K. “How Abelian Can a Non-Abelian Group Be?”. Annales Universitatis Paedagogicae Cracoviensis | Studia Ad Didacticam Mathematicae Pertinentia, vol. 9, no. 1, June 2018, pp. 99-110, https://didacticammath.uken.krakow.pl/article/view/4321.