N. González-Henríquez, M. Rey-Méndez, J. L. Catoira Gómez, M. Ruiz de la Rosa, G. Louzara Fernández, and D. G. Girard Berard, “Temporal evolution of the gonad index of the sea urchins Paracentrotus lividus (Echinoida: Echinidae) and Diadema africanum (Diadematoida: Diadematidae) in the Canary Islands (Spain)”., Rev. Biol. Trop., vol. 63, no. S2, pp. 251–260, Jun. 2015.