Mitrevichin, E. and Sakelarieva, L. 2020. Contribution to the Study of the European Ground Squirrel’s Population (Spermophilus citellus Linnaeus, 1766) in Rila National Park, Bulgaria. Studia Ecologiae et Bioethicae. 18, 4 (Dec. 2020), 75–83. DOI:https://doi.org/10.21697/seb.2020.18.4.07.