Južnič, Stanislav. “Babbageʼs Calculating Machines, the Proteus From Postojna Cave, and the Carniolan Museum Society”. Acta Carsologica 34, no. 1 (May 13, 2016). Accessed November 25, 2024. https://ojs.zrc-sazu.si/carsologica/article/view/286.