Dean, H. K., J. A. Sibaja–Cordero, J. Cortés, R. Vargas, and G. Y. Kawauchi. “Sipunculans and Echiurans of Isla Del Coco (Cocos Island), Costa Rica”. Zootaxa, vol. 2557, no. 1, Aug. 2010, pp. 60–68, doi:10.11646/zootaxa.2557.1.6.