1. Klopper, A.,The Human Placenta, Proteins and Hormones, London: Academic Press, 1979.
2. Beaconsfield, P., Villee, C.,Placenta, A Neglected Experm. Animal, London: Pergamon Press, 1979.
3. Morsy, E., Placental extracts, their composition, bioactivity and cosmetic use,Erde International, 1990, 32: 132.
4. Heldin, C. H., Miyazono, K., Wernstedt, C. et al., Endothelial cell growth factor, European Patent Application, 0 337 855, 1990-07-18.
5. Wu, K. F.,The Cell Growth Regulation Factor (in Chinese), Beijing: Science Press, 1988.