Schoenau, Luciana, Luciano Pinto, Flávia Pereira, William Schoenau, and Maria Miglino. “Gross Aspects of Macro and Microvascularization of Sheep Placenta (Ovis Aries)”. Brazilian Journal of Veterinary Research and Animal Science 42, no. 6 (December 1, 2005): 405-413. Accessed February 17, 2020. http://www.revistas.usp.br/bjvras/article/view/26398.