1. In Year Book of Paediatrics;Apt, L.,1953
2. Barandun, S., Stampfli, K., Spengler, G. A., and Riva, G. (1959). Helv. med. Acta, 26, 163.
3. Bauer, D. J., and Goodwin, L. G. (1962). Brit. med. J., 1, 716.
4. Burnet, Sir M. (1962). Ibid., 2, 807.
5. Connolly, J. H., Dick, G. W. A., and Field, C. M. B. (1962). Ibid., 1, 1315.