Jelen, Bogomir, Helena Mervič, Aleksander Horvat, and Jernej Pavšič. “Changes of the Microfossil Assemblages in the Oligocene of the Zasavje Region”. Geologija 31, no. 1 (June 30, 1988): 329–345. Accessed April 26, 2024. https://www.geologija-revija.si/index.php/geologija/article/view/616.