Calder, John H., Donald Baird, and Elliott B. Urdang. “On the Discovery of Tetrapod Trackways from Permo-Carboniferous Redbeds of Prince Edward Island and Their Biostratigraphic significance”. Atlantic Geology 40, no. 2/3 (October 10, 2004). Accessed September 20, 2019. https://journals.lib.unb.ca/index.php/ag/article/view/1041.