Project 4566: J. R. Thompson, L. J. Cotton, Y. Candela, M. Kutscher, M. Reich, D. J. Bottjer. 2021. The Ordovician diversification of sea urchins: systematics of the Bothriocidaroida (Echinodermata: Echinoidea). Journal of Systematic Palaeontology. 19 (20):1395-1448.