Souto, C., Manso, C. L. C. and Martins, L. (2011) “Rediscovery and redescription of Cassidulus infidus (Echinoidea: Cassidulidae) from Northeastern Brazil”, Zootaxa. Auckland, New Zealand, 3095(1), pp. 39–48. doi: 10.11646/zootaxa.3095.1.4.