Bielik, M., M. Janiga, and Z. Ballová. “Spatio-Temporal Distribution of European Bison (Bison Bonasus L.) in Poloniny National Park, East Carpathians, Slovakia”. Oecologia Montana, Vol. 27, no. 2, Dec. 2018, pp. 1-6, http://om.vuvb.uniza.sk/index.php/OM/article/view/311.