Amaral, F. D., M. M. Hudson, A. Q. Steiner, and C. A. C. Ramos. “Corals and Calcified Hydroids of the Manuel Luiz Marine State Park (State of Maranhão, Northeast Brazil)”. Biota Neotropica, vol. 7, no. 3, Jan. 2007, //www.biotaneotropica.org.br/BN/article/view/320.