Frykman, Peter, Ole V. Vejbæk, Niels Bech, and Carsten M. Nielsen. “The History of Hydrocarbon Filling of Danish Chalk Fields”. GEUS Bulletin 4 (July 20, 2004): 9–12. Accessed August 9, 2022. https://geusbulletin.org/index.php/geusb/article/view/4768.