Craven, Stephen A. “Postojnska Jama in Slovenia, the Südbahn and the Visit of John Charles Molteno: Their Influence on the Development of Railways in South Africa”. Acta Carsologica 35, no. 1 (June 1, 2006). Accessed November 25, 2024. https://ojs.zrc-sazu.si/carsologica/article/view/253.