Paz-Soldán, L., & Jahncke, J. (1998). The Humboldt Penguin population Spheniscus humboldti on Pachacamac Island and El Niño event 1997-98. Boletin Instituto Del Mar Del Perú, 17(1-2), 75–80. Retrieved from https://revistas.imarpe.gob.pe/index.php/boletin/article/view/176