Peel, J.S, and E.L Yochelson. “Giant Mollusca (Hyolitha) from the Permian of East Greenland”. Rapport Grønlands Geologiske Undersøgelse 101 (December 31, 1980): 65–67. Accessed July 3, 2024. https://geusjournals.org/index.php/rapggu/article/view/7722.