Vangkilde-Pedersen, Thomas, Claus Ditlefsen, and Anker Lajer Højberg. “Shallow Geothermal Energy in Denmark”. GEUS Bulletin 26 (July 10, 2012): 37–40. Accessed April 25, 2024. https://geusbulletin.org/index.php/geusb/article/view/4746.