1. Dausset, I., and Lucy, J. (1930). Paris med., 1, 112.
2. Kuhns, J. G., and Morrison, S. L. (1946). New Engl. J. Med., 235, 399.
3. Sokolow, A. (1897). Fortschr. Rontgenstr., 1, 209. Quoted by
4. Kahlmeter, G. (1930). Brit. J. Actino-ther., 5, 93.
5. Smyth, C. J., Freyberg, R. H., and Peck, W. S. (1941). J. Amer. nmed. Ass., 116, 1995.