1. Anderson JM (1972) Nature’s transplant: the transplantation immunology of viviparity. Butterworths, London
2. Austin CR, Short RV (1972) Reproduction in mammals. Book 2. Embryonic and fetal development. Cambridge University Press, Cambridge
3. Bartels H (1970) Prenatal respiration. North Holland, Amsterdam
4. Beaconsfield P, Billee C (eds) (1979) Placenta. A neglected experimental animal. Pergamon, Oxford
5. Boyd JD, Hamilton WJ (1970) The human placenta. Heffer, Cambridge