Frydrych, Małgorzata. “Classification of Esker Morphology on Soft Beds in the Area of the Saalian and Elsterian Glaciations in Poland”. Acta Geographica Lodziensia 112 (December 20, 2022): 45–60. Accessed March 14, 2025. https://ojsltn.uni.lodz.pl/Acta-Geographica-Lodziensia/article/view/1840.