Günther Nonell, J., and J. Boza Abarca. “Intensive Rearing of Juveniles of Cichlasoma Managuense (Günther 1869) in Recirculated Systems (ESP)”. Uniciencia, Vol. 8, no. 1, Jan. 1991, pp. 3-10, https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/5438.