Schovsbo, Niels H., Arne T. Nielsen, and Donald L. Gautier. “The Lower Palaeozoic Shale Gas Play in Denmark”. GEUS Bulletin 31 (June 25, 2014): 19–22. Accessed November 28, 2021. https://geusbulletin.org/index.php/geusb/article/view/4640.