1. Allen, E. V. (1948).Bull. N. Y. Acad. Med., 24; 491–504.
2. Barker, N. W. (1934).Med. Clin. North Am., 18; 597–599.
3. Birnberg, V. J., Hansen, A. E. (1942).J. Pediat., 21; 775.
4. Briggs, J. B. (1905).Bull. Johns Hopkins Hosp., 16; 228.
5. Brown, J. B. (1940).Am. J. Surgery, XLIX; 242.