Reproductive periodicity of the echinoids Diadema and Echinometra of the two coasts of Panamav. 50No. 147–61
Lessios, Harilaos A. 1981. "Reproductive periodicity of the echinoids Diadema and Echinometra of the two coasts of Panama." Journal of experimental marine biology and ecology, 50, (1) 47–61.