Kolčakovski, Dragan. “Speleomorphological Characteristics of the Carst and Protection of the Underground Carst Forms in the Skopje Basin”. Macedonian Journal of Ecology and Environment 4, no. 1 (December 31, 1996): 29–34. Accessed May 19, 2024. https://mjee.org.mk/index.php/mjee/article/view/37.