1. Adams, F. H. and Lind, J. (1957). Pediatrics, 19, 431.
2. Amoioso E. C., Dawes, G. S. and Mott. J. C. (1958). Brit. Heart J., 20. 92.
3. The Foetal Circulation and Cardiovascular System, and the Changes that they Undergo at Birth;Barclay, A.E.; Franklin, K.J.; Prichard, M.M.L.,1944
4. Researches on Pre-natalLife;Barcroft, J.,1946
5. Blood, F. R., Glover, R. M., Henderson, J. B. and d'Amour, F. E. (1949). Amer. J. Physiol., 156, 62.