1. Morgagni, J. B., quoted by Byers, R. K., & Hass, E. M., Am. J. Dis. Child., Chicago, 1933, XLV, 1161.
2. Ehlers, H., & Courville, C. B., J. Pediat., St. Louis, 1936, VIII, 600.
3. Holt's Diseases of Infancy and Childhood, tenth edition;Holt, L.E.; Jnr.; McIntosh, R.,1933
4. Byers, R. K., & Hass, E. M., Am. J. Dis. Child., Chicago, 1933, XLV, 1161.
5. Wyllie, W. G., Brit. J. Child. Dis., London, 1924, XXI, 124.