Bussing, W. A. “Two New Species of Cichlid Fishes, <i>Cichlasoma sajica</i> and <i>C. diquis</i≫, from Southeastern Costa Rica”. Revista De Biología Tropical, vol. 22, no. 1, July 1974, pp. 29–49, https://revistas.ucr.ac.cr/index.php/rbt/article/view/26058.