Rząsa, Krzysztof, and Mateusz Ciski. “Determination of the Level of Sustainable Development of the Cities - a Proposal for a Method of Classifying Objects Based on Natural Breaks”. Acta Scientiarum Polonorum Administratio Locorum 20, no. 3 (October 4, 2021): 215–239. Accessed May 7, 2024. https://czasopisma.uwm.edu.pl/index.php/aspal/article/view/6701.