1. Breed, R. S., Murray, E. G. D., and Smith, N. R., Bergey's Manual of Determinative Bacteriology, seventh ed. (Williams and Wilkins, Baltimore, 1957).
2. Carr, J. G., and Shimwell, J. L., Nature, 186, 331 (1960).
3. Jackson, C. P., and Ramamurti, K., Nature, 187, 942 (1960).