- Balen, Dražen., et all. "Cretaceous Volcanic Rock Geosites of the Papuk UNESCO Global Geopark (Croatia): Scientific Aspect of Geoheritage in Geoeducation, Geotourism and Geoconservation." Geoconservation Research (Geoconserv. Res.), vol. 6, no. 1, pp. 1-17, https://doi.org/10.30486/gcr.2023.1979814.1122