Ontological differences in first compared to third trimester human fetal placental chorionic stem cells by Jones, G, Moschidou, D, Puga-Iglesias, T, Kuleszewicz, K, Vanleene, M, Shefelbine, S, Bou-Gharios, G, Fisk, N, David, A, De Coppi, P, Guillot, P