Silva-Benavides, A. M. “The Use of Water Chemistry and Benthic Diatom Communities for Qualification of a Polluted Tropical River in Costa Rica”. Revista De Biología Tropical, vol. 44, no. 2A, Aug. 1996, pp. 395–416, https://revistas.ucr.ac.cr/index.php/rbt/article/view/21625.