Turk, Janez. “Hydrogeology of Gradišnica and Gašpinova Jama Caves in Karst Aquifer Between Planinsko Polje and Ljubljanica Springs (Central Slovenia)”. Geologija, vol. 51, no. 1, June 2008, pp. 51-58, https://doi.org/10.5474/geologija.2008.005.