Major, Maciej, and Barbara Nawolska. 2017. “Nowe Spojrzenie Na Gry Penneya”. Annales Universitatis Paedagogicae Cracoviensis | Studia Ad Didacticam Mathematicae Pertinentia 5 (July):83-94. https://didacticammath.uken.krakow.pl/article/view/3683.