Ćalić-Ljubojević, Jelena. “Natural Bridges on the Vratna River (Eastern Serbia) As the Last Remnants of a Former Cave”. Acta Carsologica 29, no. 2 (June 1, 2016). Accessed November 22, 2024. https://ojs.zrc-sazu.si/carsologica/article/view/463.