Kresten Nielsen J, Hanken N-M. Late Permian carbonate concretions in the marine siliciclastic sediments of the Ravnefjeld Formation, East Greenland. ggub [Internet]. 2002 Dec. 3 [cited 2024 Nov. 27];191:126-32. Available from: https://geusjournals.org/index.php/ggub/article/view/6434