1. Campbell, M., and Suzman, S. S. (1934). Guy's Hosp. Rep. 84, 281.
2. Cams, M. L., and Lee, H. J. (1936). Wisconsin med. J., 35, 33.
3. Christian, H. A. (1925). Rhode Island med. J., 8, 109.
4. Davis, J. C. (1931). * Ann. intern Med., 4, 733.
5. Fahr, G. (1925). J. Amer. med. Ass., 84, 345.