1. Bulkeley, W. C. M. (1953). Brit. med. J., 2, 1127.
2. Cairns, H., and Smith, H. V. (1952). In Modern Practice in Tuberculosis, ed. T. H. Sellors and J. L. Livingstone, vol. 2, p. 353. Butterworth, London.
3. Dowling, H. F., Sweet, L. K., Robinson, J. A., Zellers, W. W., and Hirsh, H. L. (1949).
4. Friedman, M. M. (1942). J. biol. Chem., 144, 519.
5. Graub, M., and Barrist, E. M. (1950). Amer. Rev. Tuberc., 61, 735.