1. Abbott, O. A., Hopkins, W. A., and Guilfoil, P. H. (1950). J. thorac. Surg., 20, 571.
2. Experiences with a New Concept of the Etiology of Pulmonary Emphysema;Van Fleit, W.E.,1952
3. Blades, B., Feattie, E. J., Jr., and Elias, W. S. (1950). J. thorac. Surg., 20, 584.
4. Carr, D., and Chandler, H. (1948). Ibid.,.17, 1.
5. Crenshaw, G. L., and Rowles, D. F. (1952). Ibid., 24, 398.