“Diatom Diversity of Springs and Spring-Fed Streams in Vitosha Nature Park, Bulgaria”. Годишник на Софийския Университет „Св. Климент Охридски“, Биологически факултет, Книга 2 – Ботаника 99 (July 11, 2025): 26–46. Accessed January 12, 2026. https://annual.uni-sofia.bg/index.php/biofac-botany/article/view/1610.