Cabrera-Sharp, V, Read, J E, Richardson, S, Kowalski, A A, Antczak, D F, Cartwright, J E, Mukherjee, A, De Mestre, A M, "SMAD1/5 signaling in the early equine placenta regulates trophoblast differentiation and chorionic gonadotropin secretion", Endocrinology, 2014