Zieliński, Marcin. 2018. “On Non-Equivalent Metrics on a Uncountable Set”. Annales Universitatis Paedagogicae Cracoviensis | Studia Ad Didacticam Mathematicae Pertinentia 9 (1):139-52. https://didacticammath.uken.krakow.pl/article/view/4319.