Callomon, John H., Peter Alsen, and Finn Surlyk. “The Ammonites of the Middle Jurassic Cranocephalites Beds of East Greenland”. GEUS Bulletin 34 (December 28, 2015): 1–86. Accessed November 21, 2024. https://geusbulletin.org/index.php/geusb/article/view/4488.