Monge-Nájera, Julián. “Retro Fashion: Did Onychophorans Abandon Ovoviviparity and Revert to Laying Eggs?”. Revista de Biología Tropical, no. 1 (January 21, 2019): Darwin. Accessed November 29, 2022. https://revistas.ucr.ac.cr/index.php/rbt/article/view/35964.