Hamlett, William C. «Evolution and morphogenesis of the placenta in sharks». Journal of Experimental Zoology, 252, S2, 1989, pàg. 35–52. DOI: 10.1002/jez.1402520406.
Jerez, Adriana; Ramírez-Pinilla, Martha Patricia «Morphogenesis of extraembryonic membranes and placentation inMabuya mabouya (Squamata, Scincidae)». Journal of Morphology, 258, 2, 11-2003, pàg. 158–178. DOI: 10.1002/jmor.10138. PMID: 14518010.
Norris, David O., Ph.D., Professor Emeritus, Department of Integrative Physiology, University of Colorado at Boulder, Colorado, USA,; Carr, James A., Ph.D., faculty director, Joint Admission Medical Program, Department of Biological Sciences, Texas Tech University, Lubbock, Texas, USA. Vertebrate endocrinology. (en anglès). 5a ed., 2013, p. 349. ISBN 978-0123948151 [Consulta: 25 novembre 2014].