Monge, Julián. “Are the Eggs - Kept and Fed by the Mother - the Ancestral Form of Reproduction in Onychophorans?”. Revista de Biología Tropical, no. 1 (March 5, 2019): Darwin. Accessed April 17, 2024. https://revistas.ucr.ac.cr/index.php/rbt/article/view/36398.