Jordanoska, Biljana, Manuel Kunz, Trajče Stafilov, and Alfred Wüest. 2010. “Temporal Variability of Physico-Chemical Properties of St. Naum Karst Springs Feeding Lake Ohrid”. Macedonian Journal of Ecology and Environment 13 (1-2):3-11. https://mjee.org.mk/index.php/mjee/article/view/92.