Brøgger Sørensen, Peter, Holger Lykke-Andersen, Peter Gravesen, and Bertel Nilsson. “Karst Sinkhole Mapping Using GIS and Digital Terrain Models”. GEUS Bulletin 38 (July 31, 2017): 25–28. Accessed April 25, 2024. https://geusbulletin.org/index.php/geusb/article/view/4392.