1. BULGIN, D., LLEWELLYN, F. J., THOMAS, GARFIELD (1949), The Lancet, May 7.
2. HOSPITALS, Journal of the American Hospitals Association, December, I949.
3. WOODBRIDGE, P. D., HORTON, J. W., CONNELL, K. (1939), Journal of the American Medical Association, II3, 740-744, August 26.